Pacemaker Boat Owners Association

I went through this and due to the anti freeze in the crank case I repowered the boat. If you find the problem and fix it you could gamble and change the oil out two or three times in a short period of time and you might be ok. I went with the repower as I did not want to take a chance with an engine that had a lot of hours on it to begin with. What is your oil pressure like?

Oil pressure was about 60 psi until I blew the remote oil filter oring I have flushed the oil about 4 times. The log manifolds and riser are the ones I have had for about 3 years but only used them about 3 times. I am currently looking to convert from log to center manifolds. I believe that the manifolds are toast.

If you are sure the manifolds are the problem then I would not run her any more till you fix them.

I dont plan on running her until she is fixed

Are there any test I should do before giving up? The mechanic is charging me 95 an hour for diagnoising is that good or bad? What should I do in this case compression test, leak down test, or just replace the motor. I recieved the motor from a friend a few years ago he said that they repowered there boat. I dont want to have to spend alot of money for nothing please advise me on what to do. Thanks in advance

95/hr is on the better side for marine engine work but having a "pro" not be able to figure it out after a few attempts is not good.
What engine? How many hours? Has it been overheated? General history?
If manifolds and risers check out, I'd be looking at head gaskets.

Mercruiser 350 approx 26hrs temp 165 max log style manifolds just replaced the gasket to the riser fresh water cooled doing a leak test and copression test today. I will also be pulling the motor and tranny out until it is fixedfor sure :( not wanting to do this but it has to be done.

Not to sound demeaning but: Log manifold/riser- did you put the right gaskets in the right spots?
Was it ever overheated?
If the engine truely has only 26 hours, having the actual manifold leak (unless stored with water and cracked) dosen't seem all that likely?
Unless you plan on a tear down until you find a leaking gasket, I would leave it in the boat. It will be easier to run it under a load to check if got fixed.

Yes they are in the right spot. I have already pulled the motor and I will be doing some test on it until we figure out what is wrong with it. My goal tomorrow is to get the motor in my garage

Well I just got the motor out of the boat and in the garage. I drained the oil and filled the oil pan with diesel, did a compression test and it was sat at 120 psi. I flushed the block with fresh water coming to find out that there is rust particles. I flushed unntil I could find any more particles in the water. I started to do a leakdown test on the cooling system and so far she is holding at 15 psi. tomorrow I will hopeful get her started and figure out if she needs some more attention. I plan on getting some of the descaler and runnig it threw the block, check to see if there is water actually getting in oil and if the overheating is caused by the rusted cooling passages.

Well I had the motor running today it seems that the water is overheating still. run the motor for ten minutes and the it is just flow the out the over flow nipple on the heat exchanger i pulled the thermostat not sure if i put it in the right way so I flipped it will run again tomorrow ran some descaler through the block and no more rust came out. Leak test on the cooling system held 15 psi overnight so it is good to go. Anybody have any other advice for troubleshooting on why the motor is overheating? Does anyone know the timing for a mercruiser 350

You might have clogged exhaust elboes.

will check then tonight if i dont pass out from work

well I have take the logs off and flush all the rust and scale out of them flushed the block 3 times until the rust colored water is out hopefully not more over heating issues. The temperature on the logs while running is about 160 -190 degrees. I have talked to a few mechanic and they are pretty much telling me that this issue I am having is weird. I have a timing issue she is running at approx 22 degrees btdc with vaccum advance hooked up is this normal? I will be op testing tomorrow hopefully al goes well.

Unhook the vacume advance when yo try to time it. Did you pressure test the logs, risers and elboes?

The leak test would seem to discount this as a possibility, but it is possible that water is entering into the crankcase via the intake manifold to cylinder head joint. There are water passages at the front and the back of the head that are open to this surface. If the engine has been rebuilt and the heads were resurfaced, the gap between the head and manifold can be larger than desired and result in leakage.

Regarding the exhaust manifolds, risers, and elbows: check for obvious cracks and erosion of metal due to corrosion - especially of gasket surfaces between these components. The region in the elbows where water is expelled from the cooling jacket into the exhaust passage should not be too eroded. If they are excessively corroded, this water could be exiting in the wrong location and back-flowing past the risers and into the manifold.

Regarding the overheating, I was having a great deal of problems with my Crusader 350 due to air pockets in the cooling system. This seems to be exacerbated by the extreme angle at which the engine is installed in the 25/26-footer. The propeller shaft angle is 15°, which is about the limit. I actually ended up drilling and tapping the top of my thermostat housing in order to permit me to bleed air trapped in the front of the engine out.

Regarding the timing...refer to the owner's manual of the engine and set the timing properly. Usually this is done with the vacuum advance disconnected (but plugged).

I did not pressure test the logs and riser but I did get alot of scale out I will run the motor and tranny tomorrow since my work kept me late

well I have installed some clear hose on the logs to see if there is exhaust gases getting in the cooling system but no bubbles present. Ran the motor and closely monitored the clear hoses it turns out that there are air pockets due to the angle of the engine and a rear mount heat exchanger. Bled all the air out of the system and presto she cools like non other.

Now that was a neat idea with the clear hoses.

I saw it on you tube. Works very well for checked if there are exhaust gases entering in thru the logs