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ABA Boat Maintenance & Repair Questions and Responses

The information contained herein is the opinion of ABA member and marine mechanic Tim Harrington of Madison Marine Service, Harwich, Massachusetts. Tim is responding to a question solely based on the information an ABA member provided. Neither ABA, nor Tim Harrington, nor Madison Marine Service assume any responsibility or liability for events that occur due to actions you or others on your behalf take based on the information given in Tim's response.  You are proceeding at your own risk.

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Engines

Q. I live on the Gulf in South Alabama where we only occasionally have freezing weather. Is it still necessary to winterize and if so, is just draining the lower unit sufficient?

A. Considering your location, you should not have a lot of concern for frost damage. However, I would recommend that you change your gear oil and perform the remedial maintenance that should be done during your down time. I would also at least fog your engine for storage. This keeps the cylinder walls coated. Also, run some fuel store through the system so your carburetors do not coke up on you during the first few months you are out of the water. Before you start your season, give the boat a good check, including your plugs and the water separator (if you have one).

Q. We have a 1984 Sea Ray Sundancer with a Mercruiser engine. We had electrical problems last season. Our charger was replaced. Barnacles appeared on our lower unit. Did the electrical problems cause the barnacles? Also, if the lower unit is not scraped and painted, will this cause any problems?

A. The electrical problems you had may have caused electrolysis on the lower unit if you had no zincs or your zincs were gone. The barnacles will grow no matter what. In your down time or during spring commission, clean and prime your outdrive and let dry completely. Then apply several coats of factory or equivalent paint and also let that completely dry. Once this is complete, you have to apply several coats of clear antifouling. This will help with the growth encountered during your boating season.

Q. I have a 1990 Sea Ray 260 Overnighter with a Mercruiser 310. I have been having irregular RPM output at any speed. My max RPM output is around 4000-4100, but frequently the RPM will drop to 3100-3600. The engine (7.4L V8 454) is supposed to put out 4200-4600 RPM. I have new plugs, wires, distributor, rotor, and replaced my fuel filters. Is this problem common, and what else can I do? Thanks

A. Changing the fuel filter is a good idea. Have you checked it again? You could have contamination in the tank. Your boat would have run ok for a period of time and then drop cylinders due to moisture again.

Have you checked your coil for arc? Have you made sure your wires are on the correct cylinders? The biggest question, have you done a compression check and made note? Sometimes it could be as simple as your prop slipping. Over time the prop hub dries out and that will make rpm go up and forward speed drop. If it is intermittent it could explain your tach readings.

I hope this has been helpful and I would suggest you purchase a manual if you haven't already. It saves time with trouble shooting.

Q. I have a clanking in my distributor and my motor backfires at high speed. My distributor has oil in it. Is this base pressure?

A. If you take off your distributor cap and remove the distributor you will find the stem broken and/or the weights broken. It sounds like time for maintenance before you create more problems. Sorry for the bad news but once done you will be back on the water.

Q. We have a 1998 Donzi Sportdeck with a Mercruiser I/O. Our boat had a hydraulic lock in June. It just had another in December. As I understand it, water gets into the cylinders and the engine won't start. In June we spent $5000 to get fixes to the manifolds. The marina "pickled" the engine. Can you give me a layman's description of this problem?

A. There are many reasons why you are getting raw water into the powerplant. It sounds like it has been going on for some time from the little bit of information given. You stated that you had $5,000.00 worth of work done to have your manifolds replaced. I am guessing that your risers were also worked on.

Pickling the engine means to clean out oil and water residue from the interior of the combustion parts and block. It sounds like your engine was dismantled and rebuilt to be completely sure you have no further problems. Hydrolock is self-explanatory - water in the cylinders creates a vacuum that stops progressive motion of the operating criteria of your powerplant.

Q. I want to replace my engine. I have a friend who has a Mercruiser 350ci 230 hp 1987 I/O. I have an inboard. Can I use my friend's engine and will it need any thing done to it?

A. You can do your exchange with your friend. However, in my opinion, the bad news is that it will cost you more in labor and parts than it's worth. You can buy a rebuild and install it with a heck of a lot less trouble and aggravation. It would be nice to work on this with your friend, but I'm afraid it would become a project.

Q. I have a 1988 SeaRay 268DA with a 7.4L Mercruiser (330Hp) with an Alpha One drive. I am trying to remove the drive for winter storage and am having problems. I have purchased the shop manual and have followed the instructions. With hydraulic rams removed, clutched in forward, and 6 lock nuts removed, I can only get the drive out about a quarter of an inch. There is a fair amount of play in moving the drive up and down on the studs and from what I can see it is well greased, however, I can't get it off. This is my first year with an I/O, so I am hesitant to apply too much force. I am hesitant to try prying it off because I don't want to harm the gasket surfaces. Since the drive came out 1/4 inch without any force, I am wondering if it is hanging up on something inside the housing? Any ideas?

A. With regard to your outdrives you are ok. Sometimes they get hung up in the gimbal housing and make it a little tough to get off. Disregard the worry about your gaskets because you have to replace them anyway. If you take a small block of wood, (I prefer pine or soft wood) and put this at the base of your drive, you can use this as a lever to add pressure to the drive unit and get her to pop off. It will come off. Chances are the gimbal housing and gimbal ring need some servicing. When done, spin the gimbal and make sure everything is ok. Otherwise you will re-install your drives just to have problems in the spring. This should help your dilemma and by using soft wood it stops damage that may occur when using a hard wood lever.

Q. Just wanted to know how difficult it is to change the water pump on the Alpha One Outdrive. And if there are any tips or methods for doing this more easily, since I have never done this before.

A. My advice is to get either a Mercury manual or Clymer manual that will cover your equipment. Take the numbers off your engine and outdrive to make sure they match the manuals you purchase. Use the outdrive Alpha One book to take off the lower section of your outdrive. This will give you the access to your pump assembly. Make sure to purchase the correct replacement kit. This is something that you can do, just put the manual to work and you will do fine.

Q. I purchased a 1996 Crownline 202BR with a Mercruiser 5.7L from the original owner in March of 2003. I am now having trouble with the trim. I used the boat three times and the motor would not come up. The mechanic replaced the solenoid and that seemed to fix the problem. I used the boat a few more times with no problem and then suddenly the trim would not work again with the motor stuck in the down position. This time you could hear a clicking when the trim switches were pressed. I docked the boat at the same marina that had worked on it before. I went to check on it the next day and tried the trim and it worked. I brought the motor up and got it ready to put on the trailer. By the time I got from the dock to the trailer (not far) the trim was no longer working. I left the boat but the mechanic never got to it so I went to pick it up and the trim was again working. I have not had it back in the water since but the trim is still working. I also found out that the original owner had a solenoid put in last year. It doesn't seem to be a solenoid this time. Could it be something to do with the circuit breaker on the trim motor?

A. I would suggest that you make sure your trim and tilt switch at the remote control is functioning. After doing this, I would check the trim motors and make sure they are working properly. If so, you may have a problem with either a connection and/or the trim limit switches and your drive itself. You will see two plastic caps on the top of each side of your lower unit. One is for up and down movement and the other is the limit for height. This may be were your problem lies.

Q. I have pulled my 2001 20' Astro Bow Ride for the season In the process of trailering my boat, I have discovered that the lower unit hydraulics will only bring my engine to its regular trim point - where it normally stops. When I push the switch further to bring the engine up to its farthest point, it does not operate. I checked the switch on the throttle and it seems to be working properly. Also I checked the hydraulic fluid and it is almost full. I believe there must be a limit switch near or on the engine. Am I right? If yes, where is it, and if not, what else should I check? Thank you.

A. I think you will find on your throttle control your trim switches are working the way they are suppose to. On the arm of the control is a button that is used as a trailer switch that will bring your drive to its highest point and then you will find you can trailer your boat.

Q. Took my 1984 18' Sunrunner into the shop. The engine died every time it was put into gear, had not been used for approx 4 years, same gas. The shop finally called and said that shift cables and bushings need replaced and gave me an estimate of $700-800. I told them I was going to wait and would pick up boat. They said the outdrive is off the boat and they would put it in the boat or in my truck when I come in. My question: is it normal for the outdrive to be removed to explore my problem? Is it normal for the shop to leave it off if the work is not going to be done right away? Does the price sound somewhat reasonable? Thanks.

A. This explanation may sound odd to you, but this is the way most marinas operate once the owner puts a stop work order on a job. The marina will provide the service requested and if there is a stop work order, that's where the work comes to a halt.

If the lower shift cable needs replacing, it makes no sense to put the drive back on just to have to take it off again to finish the maintenance that needs to be done.

Also it's not a bad way for your marina or yard to do business. They did the task that was asked, and they did not create an unexpected expense for you. Can you imagine coming in, having the job being completed and tested and then being presented with a bill that is completely unexpected?

As far as the price quote, in my opinion, it is in the ballpark, and in some places it could be even higher. To answer your question, I believe that they have helped you a great deal and did not charge you for a re-installation of a drive that needs to come back off to complete the task. I hope this helps put you at ease and it sounds like you have a good facility doing your maintenance.

Q. Why is synthetic oil specifically not recommended by Mercruiser for the 4.3 engine?

A. I have not checked with Merc directly, but I would think there might be problems with performance to engine and viscosity breakdown of synthetic oil. Personally I do not use synthetic unless it is recommended or stated as an acceptable alternative to oils. If your engine is one of the new 4.3s, I think they recommend 25/40 or something like that. You need to use what is recommended by the manufacturer to protect any warranty you may have on your engine.

When I have catastrophic failure in a new piece of equipment or if something is out of place with a failure, I send out my oil and other liquids for analysis and try and determine the failure problem, and manufacturers do the same. I would use what is factory recommended to protect yourself and your equipment and to keep any current warranty valid.

Q. With 4 average sized people on board and no additional equipment I cannot get my 13' Boston Whaler up on plane. By moving the bolts I could trim the engine down one more step. Is this the thing to do or is there something else to try? Or is this the best I can get from this rig? Thanks.

A. You have a great boat and equipment, but with 4 adults in your Whaler and your 40 horse power engine, you are most likely getting the best performance you can ask the boat to give you. Take into consideration the average weight per man plus equipment to what she can produce in thrust - it does have limitations.

I hope this has helpful, but it seems that you had already reached the same conclusion.

Q. I need to bleed the tilt-trim pump and cylinders. Can you walk me through the process? Thank you - there are absolutely no competent boat mechanics within a 100-mile radius of where I am located. Thanks again for your help!

A. The easiest way to do this, depending on access to your connections at the trim tabs themselves is to disconnect at the tab end. With a small container use the trim motor to push the fluid out through those fittings to get as much as you can out. You have to listen carefully and discern when the motor is running out of material to pump, so that you do not burn the pump.

The only other way is to drain at the pump motor, but that will not help you if you want to completely purge your system.

Q. I just purchased the new engine (Honda 200) for my 2001, 23' Bay Hawk. It has a four-bladed/21 pitch prop, 25-inch shaft. Problems- 1. the boat comes out of the hole real slow, it takes 300 to 500 feet to get up. Max rpm's-4000, after about 300 yds the boat starts porpoising without any trim movement. Is there any thing I can do to help my situation?

A. I have rigged and installed Honda's for a dealership here on Cape Cod. You're way below your rpm, especially on a brand new 200! You will only get the performance of your engine's capability at max RPM by matching the proper prop with your power! I am sure you can watch your RPM change as you try different props.

My suggestion is to go to the dealer or direct to the Honda web site, www.honda-marine.com/hmframeset.htm for support to find the correct pitch for your engine. You will find a great deal of performance and speed change if you do so.

You have a great engine, fine tune her and it will serve you a good many years.

Q. I heard a grinding noise when I tried to start my starboard engine. I pulled the starter; it was broken so I replaced it. It made the same noise. I can turn the engine over by hand. So why is my starter grinding? Could it be hydro-locked? If so, what causes that?

A. I have received your question regarding the grinding noise you hear when you start your starboard engine.

You want to know if your boat was in hydro-lock. If you can put a breaker on your engine and turn it, you are not in a locked state.

There are a few reasons why you are hearing the grinding sound. One reason could be due to water ingestion.

Have you ever replaced your flywheel? If so, does it have the right number of teeth for your engine? If not, that could explain the grinding noise.

You mentioned that you placed your starter. Did you replace it with the correct marine starter? Marine starters are closed to spark for inboard tanks! Also, make sure you use your blowers.

You may have improper meshing of your starter pinion and flywheel ring gear. Check the starter pinion gear and see if the teeth are chipped or worn. Check the flywheel ring gear for the same thing.

I hope that by checking the things mentioned above, you will find the source of your grinding noise. If you're going to trouble shoot the problem yourself, I suggest grabbing a service manual. It will also help you with any necessary repairs. As always, if you have any doubts about what you are doing, turn to a qualified technician.

Q. The trim motor will not hold the trim, but it is not leaking fluid externally, what could be wrong?

A. I have only worked on a few force motors, but chances are either your trim motor or the plumbing are getting air somewhere in the system. Being a 1986 motor, you are dealing with a trim that is 16 years old. If you have excess corrosion, you may not be seeing the static or pressurized leak. It may be time for new motor. If is a side mount, it is a fairly easy job to replace.

Q. I have just had my carb rebuilt and my performance has increased greatly, at take off and speed. I am still having trouble with the engine stalling about 60% of the time when I pull the throttle down to neutral or try to reverse from an idle forward to reverse to dock, here it dies about 90% of the time. The friend that overhauled my Rochester 2bbl carb is a GM master mechanic but has said that he would like some direction from a marine expert. Any ideas to check or solutions?

A. It sounds like things are okay with your carb, and I do not believe a master technician would have a problem with a rebuild kit. From what you're telling me and not knowing the year or serial numbers to your inboard, I don't think your problem is in your carb. You seem to have idle and high rpm with no interference, and it sounds like when you are in low rpm range and shift from forward to reverse at low rpm, you stall. Based upon this, I would look to the interrupter switch, if you have one, and/or your lower shift cable. Take your serial numbers and look at the manual to your engine. Here you'll find rigging and all of the other parts we just mentioned. Troubleshoot by checking the shift cables and interrupter switch to see which is the culprit. Your mechanic friend sounds well qualified to help and the manual will fill in the gaps for him. Hope this is helpful in getting you in the right direction.

Q. My RPM is not working. I have checked behind the gauge itself and all the connections seems to be in good shape. Do you have any other suggestions? It's a 1999 Johnson Motor 115 HP.

A. Your question was about your tach not working on your OMC outboard. You stated that you have looked at your connections and they looked fine. Even so, I would recommend that you remove them, clean them and reconnect. Go to the engine and match your wiring from your harness and check that everything is correct. If everything is ok, you may be having problems with your gauge itself and/or the sensors at the power head that send the rpms to the gauge.

If this seems to be the case, I suggest that you have a qualified technician do an ohms test for you. It will not take much time to do an ohms test and it could tell you what your problem is.

Q. My '77, 75HP Chrysler outboard refuses to start. The motor turns over, but there is no spark to the distributor and beyond. I think it may be due to a bad power unit (a.k.a. CD unit) because the unit gets quite warm when I turn the key to the "on" position. I don't want to have to replace it, because it is a costly part, if I don't have to. Do you have any thoughts, ideas, suggestions, etc?

A. I do not believe, based on the information that you gave me that you have much choice other than replacing it, especially if it is heating up during cranking operation. After 25 years in service, I think it has served you well.

You may be able to save some money if you check out Sierra products. They are sold on the Boater's World website, which you can link to thru the following ABA site, Products.

I am sorry for the news, but I don't think you have much choice. I hope you're on the water soon.

Q. Temp goes up as throttle is increased. Reduce throttle and temp comes back to normal at 2500RPM.Problem appears to be on starboard side. Infrared show port to be about 120?. Can you think of a cause? I had the boatyard work on it last year. They reduced temp, but not to a normal range

A. I received your question from the American Boating Association. If I understand your question correctly, you have a temp fluxuation when throttle is increased with your port engine. As you increase RPM, your temp rises and it returns to a normal range at 2500 RPM. You used a heat gun to indicate what the correct reading was at 2500 RPM. (Returned to 120)

 It sounds like your pump and thermostat were replaced at the boat yard. I don't believe that this is the cause of your problem, as you would completely overheat in high RPM if they were involved.

Based on the information you have supplied, I would start looking for blockage within your cooling system. Your boat is twelve years old and I do not know whether you run in salt or fresh water. Check all your hoses and your water flow. Make sure your inspection includes risers and manifolds for restriction. Also check your water assembly and drive and make sure the recommended thermostat is in place. It sounds like a definite restriction problem under pressure. If you have ever lost water pump impeller due to wear or drying out, check inlet restrictions for pieces of rubber that would restrict water flow. You are probably going to narrow this down by checking for restriction in these areas. I hope this helps you get to the bottom of your problem.

Q: I have a Chekmate with a Suzuki 115 horsepower motor on it, it is a speed boat what should my top speed be?

A: I would say that at 115 HP, a 16' Checkmate should move right along! The best way and most exact way to determine your top speed without a speed gauge or picking to locations on land and timing yourself at your high rpm range, is to use a GPS. If you do not have one, maybe you could borrow one. Without a speed gauge, this would be the most reliable way to tell your speed. If your engine is carbureted, your RPM should be between 5500 and 6000. This is high end! Do not run the boat for long periods at max RPM, though. Have a great and safe boating season and try to keep it under a 100!

Q: I have a problem with my boat. It seems like it won't change gears. I have a Mercruise inboard/outboard with a 4.3l. It has an Alpha One outdrive. Can you give me any advice?

A: I would like to give you a starting point for your problem. Your engine to outdrive is mechanical shift. On the top right side looking forward you will see your shift cables. Not knowing how old your cables are, I would check the standard measurement for your cable. From the center of the mounting end to the center of the hole in front should be 6 inches. This should rig your shifting cable closer to working correctly. If this does not help, it is probably time to change the cable. If you have a problem with going into reverse with stalling, chances are it's your lower shift cable. Check your throttle box for operations. To change your shift cable is not a hard job but may be time consuming do to the routing. Your lower shift cable is a different story, not bad but outdrive has got to come off. Before doing this, obtain a manual. They are inexpensive and it will save you any guesswork. Also, if you are going to change both cables or if your boat is out of the water, it is a good time to check your outdrive gear oil. Do not re-use the old gasket and O-rings. Hope this gets you going.

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