Engine dead

PAUL1966 · Apr 11, 2012

Hi looking for some hope.
Bought a Bayliner 2665 last year with a 7.4l engine which was dead. Got a 2003 Mercruiser 5.0l MPI 260HP with a bravo 111 drive with 120hrs from a dealer.Only had it out a few times and had to get towed back. Trying to get it fixed for this year and did a compression test on it this morning and it was bad psi was from 50 down to 27.
Got on to the dealer and they want me to bring the boat uo to them (about 500km away) but dont know if i can trust them. I was thinking will i try and take off the head myself but dont know if it might be to big a job.
Can anyone give me an idea what might be gone.
Thanks

Scott Danforth · Apr 11, 2012

Re: Engine dead

did you winterize it?

did you have it out a few times this year?

did it over heat?

are you trying to do a compression test on an engine that sat over winter? if so your rings could be stuck. squirt a bit of oil down the cylinders thru the spark plug holes and re-test. if the numbers go back up to 150ish, then you may simply have stuck rings from sitting.

Dshow · Apr 11, 2012

Re: Engine dead

Was the compression test run the the engine warm and throttle open? There is a Merc service buletin I've seen here recently on how to perform... Fifty sounds low to begin with. How many cylinders?

PAUL1966 · Apr 11, 2012

Re: Engine dead

Scott Danforth said:
did you winterize it?

did you have it out a few times this year?

did it over heat?

are you trying to do a compression test on an engine that sat over winter? if so your rings could be stuck. squirt a bit of oil down the cylinders thru the spark plug holes and re-test. if the numbers go back up to 150ish, then you may simply have stuck rings from sitting.

No didnt winterize it
Not out anytime this year.It wont start.
It never overheated

PAUL1966 · Apr 11, 2012

Re: Engine dead

Dshow said:
Was the compression test run the the engine warm and throttle open? There is a Merc service buletin I've seen here recently on how to perform... Fifty sounds low to begin with. How many cylinders?

The throttle was open the engine cold as i cant get it to start.
8 Cylinders

Scott Danforth · Apr 11, 2012

Re: Engine dead

first off, where do you live? It helps us understand, especially if you did not winterize and you live in an area that has freezing temps.

if you live in a warm climate area, you may just have stuck rings. again, squirt oil in the cylinders, and make sure the throttle is open, then re-run the compression test. you will need to have a fully charged battery as well.

PAUL1966 · Apr 11, 2012

Re: Engine dead

Scott Danforth said:
first off, where do you live? It helps us understand, especially if you did not winterize and you live in an area that has freezing temps.

if you live in a warm climate area, you may just have stuck rings. again, squirt oil in the cylinders, and make sure the throttle is open, then re-run the compression test. you will need to have a fully charged battery as well.

I loive in Ireland and the winter was quiet mild had no freezing temps.
Will try the oil later today hope it will make a difference.

Scott Danforth · Apr 11, 2012

Re: Engine dead

even with mild winters, its a really good idea to winterize. draining the block and manifolds when the boat sits for a long time is always a good idea. if your block was full of water and you did get an overnight freeze or two (not uncommon even in Ireland), you may have a cracked block etc.

PAUL1966 · Apr 11, 2012

Re: Engine dead

Scott Danforth said:
even with mild winters, its a really good idea to winterize. draining the block and manifolds when the boat sits for a long time is always a good idea. if your block was full of water and you did get an overnight freeze or two (not uncommon even in Ireland), you may have a cracked block etc.

Had thr problem before the winter

fmalott · Apr 11, 2012

Re: Engine dead

PAUL1966 said:
Hi looking for some hope.
Bought a Bayliner 2665 last year with a 7.4l engine which was dead. Got a 2003 Mercruiser 5.0l MPI 260HP with a bravo 111 drive with 120hrs from a dealer.Only had it out a few times and had to get towed back. Trying to get it fixed for this year and did a compression test on it this morning and it was bad psi was from 50 down to 27.
Got on to the dealer and they want me to bring the boat uo to them (about 500km away) but dont know if i can trust them. I was thinking will i try and take off the head myself but dont know if it might be to big a job.
Can anyone give me an idea what might be gone.
Thanks

you said you had it out a few times so you were actually driving a good running boat and then it died on the water. to me it sounds like the head gasket blew or something went wrong with the head maybe valves. with my limited experience i never seen rings sieze while the boat is running. i know it has nothing to do with the compression but no one mentioned it do you have good spark and does it turn over very well?

Bondo · Apr 11, 2012

Re: Engine dead

I was thinking will i try and take off the head myself but dont know if it might be to big a job.

Ayuh,.... Diagnostics, save money, 'cause you learn to Know where to look for the real Problem,...

If ya just pull the heads, yer diagnostics window is Closed....

You need to do not only a compression test, but also a leak-down test, to see where it's leakin' off,...
Through the rings, or pistons, or valves...

Don S · Apr 11, 2012

Re: Engine dead

I sure wouldn't worry about compression numbers being low on an engine that has been setting for several months. At this point, even if it did freeze and cracked the block it wouldn't cause the engine to die out on the water last year.

Since the engine died, have you checked for spark at any time? If you turn the ignition switch to the run position, do you hear the fuel pump run for 2 seconds and stop? The MPI engines have a lot of fuses, relays, etc. to look at before you start pulling the engine apart.
I would bet if you got the engine started and ran it for just a minute or less that the compression numbers would get much better.

PAUL1966 · Apr 11, 2012

Re: Engine dead

Bond-o said:
Ayuh,.... Diagnostics, save money, 'cause you learn to Know where to look for the real Problem,...

If ya just pull the heads, yer diagnostics window is Closed....

You need to do not only a compression test, but also a leak-down test, to see where it's leakin' off,...
Through the rings, or pistons, or valves...

How do i do a leak down test?
Will do a few more tests on it in the morning. Hopefully something will work
Will try a few of

PAUL1966 · Apr 12, 2012

Re: Engine dead

Update
Put oil in the engine and re did the compression test went from 25/50psi to 50/65psi
checked the sparks and all seems ok there
checked the fuel and flow seems ok.
im going to put in new plugs today and see if it will start.
Any ideas of anything else i could do to help it to start?

Scott Danforth · Apr 12, 2012

Re: Engine dead

if your compression did not come up to 130-150 range by squirting oil in the cylinder, you still have low compression.

next you should do a leak test of each cylinder.

Engine dead

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