I need some help with the engine in the doner boat I bought to power my islander.
Looked at the boat, has 331 hours on it. The entire drive line looks great, and appears to have very little wear. I checked the oil before we did anything and it looked good, right at the top of the fill line.
History: The boat sat at a marina in indoor storage for 20 years, got sold to a local boat salesman when the marina went belly up. The salesman decided not to full with it and put it on craigslist for cheap. (trihull with a soft floor) I went to check it out. The first thing I found was the ignition did not work, so we tried to start the motor by jumping the solenoid. It would crank, but not fire. I got it to finally run by dumping a little bit of gas down the carb. (Accelerator pump on the Rochester 2GC was not working.) It ran four about 5 minutes then stalled after I put it in neutral to get it into gear. (Idle speed was too low.) I tried to get it to start again, but it didn't want to catch again. The carb needed a rebuild, everything on it was pretty sticky. I checked the oil and again everything was fine. I paid the man, and drug it home happy to have cheap power for the islander.
Fast forward to today
I bought a rebuild kit for the carb and it came in. I replaced the seal and spring on the accelerator pump, and put a new gasket on the airhorn assembly. I didn't open it up any farther because it was spotless inside, and I already knew it would run. I cleaned the choke parts well and they move freely now. Checked the oil and it's still fine. I put the gas to it, pumped the throttle a couple of times and jumped the solinoid and it fired right up, purring nicely! It barely smoked at all on the start and started pumping water quickly. The water ran with a bit of rust in it at first, but quickly cleared up.
I ran it for 5 or 10 minutes on the hose to check it over and warm it up so I could give it an oil change. When I was checking it over I noticed a quarter sized puddle of water bubbling on the and head right were the gasket is. I belive it was slowly boiling which was causing the bubbles. When I looked at it closely, I could actually see water bubbling up through the center of the gasket in a different area! Horrified, I shut it down.
I check the oil and sure enough, it is showing signs of water. The oil level on the dipstick was not noticably high. The old engine in my islander had cracked due to a bad manifold/riser letting water onto the piston, so even though it was winterized it cracked the block when that water froze. I am hoping this isn't the case and it's just a simple maniflod or riser problem, but who knows. Im figuring a cooling system presure test will be the ticket, and a compression test on the cylenders but I don't have any tools to perform these tasks at the moment. Anyhow, I decided to check what I know I could right now and see what information I could gather to help
diagnose the problem.
First thing I did was suck out all the oil with my oil extractor. I opened the plugs on the block and manifold and let them drain. The water was clear that came out of them both.
I pulled all the spark plugs and took a peek inside with a powerful flashlight. The pistons were all dry. #6 looked like it may have had moistiure in it at one point but there wasn't any sitting on the piston. It just had a darker look to it than the rest, but seemed to be dry as well.
Now the $1,000,000 question. Where do you think the water could be coming from and how do I check it? I assume a new manifold and riser combo are needed, and the leaking gasket should be replaced and everything torqued. If the maniflold was the culprate I would expect to see water on the pistons? How else could it get into the engine?
I am going to pull the engine from the boat to put in the islander anyway so nothing is out of the question for checking. If worst comes to worst and the block is cracked, I have two blocks sitting in the shop that could be made to work.
On a positive note, the drive worked flawlessly on the hose, the gible was quiet as was the universal joint.
I'm thinking I have a gasket problem. The motor was winterized when I first looked at it (Plugs were both out, dry as a bone.) I don't know if somehow she loosed up a bit and the torque for head bolts, manifold ect. could be loose? I think I'm going to get a gasket set and pull the manifold and head off of her and see what's going on. Hopefully it's as easy as that, but I'm just guessing at this point.
On a seperate note, how to you tell if a manifold and riser are ok? When are these replaced? I would like to keep a good manifold and riser on the boat and not have to be constantly worrying if it went bad on me. Are these a typical item to replace every couple of years?
I am pretty familiar with this. You are probably going ot need to take the top of the engine apart, and change the gaskets, and likely the freeze plugs in the head. It is under the intake manifold. Also you may have an exhaust leak through the gasket causing the bubbles.
You can still get the part manual for the intake manifold, and all those gaskets from OSCO. And just take the manifold and riser apart, and look it over really good. You can find any rust through if you poke it enough from the inside once it is off.
If gaskets and feeze plugs are what this leaking is all about then GREAT!! I guess I need to bite the bullet and take the head apart one of these days... Other than this little problem the engine seems great. It looks great, starts well and purrs like a kitten. If I can stop this water leaking nonsense the islander will be in business. I thank you very much for your help!
Im looking to buy a gasket set for this engine either tonight or tomorrow. From what I have been reading the Mercruiser gaskets are the good ones, and I imagine Felpro is a good gasket too. The problem is I have not been able to find any Mercruiser gaskets for this engine. How would something like this work? http://www.ebay.com/itm/MERCRUISER-1...sories&vxp=mtr
I guess I will need the Head gasket, Valve cover gasket, and a manifold gasket at a minimum. Is there anything special that needs to be done on these gaskets for installation other than torque to spec? I thank you for your time!
Before you go out buying gaskets, pull the riser and manifold off and evaluate their condition. You might be able to visually tell if it has been leaking and where. I'm a little unclear as to where you mention the water is puddling and bubbling. There is not a water passage between the head and exhaust manifold.