Not Turning Over, Low Compression, Mercruiser 3.0

[ronaldreagan]

Really happy to find the cause, stuck rings. Now time to fix and rebuild. What sites do youse use for internal engine parts?

 

[ronaldreagan]

I replaced the rings, honed the cylinders, and new gaskets. Connected to my car with jumper cables.... The compression is 110, 105, 110, 100.

I'll connect it to proper battery terminals later to see what I get.

What do you think?

 

[alldodge]

That's not good it it will run with those numbers, but will be lower or HP

 

[ronaldreagan]

That's not good it it will run with those numbers, but will be lower or HP

I did it again but this time with proper terminals but again connected to my car battery. It cranked much stronger and gave me 115, 120, 120, 120.

Definitely an improvement from 70, 45, 30, 50 prior to replacing the rings.

This was just after reassembly, without running the engine prior. What should the compression be for a Mercruiser 3.0?

 

[alldodge]

New would be 150, but what you have done so far, could be good for a good while. Pressure will come up a tad more when warmed up

Don't know if your gauge is accurate

 

[achris]

.... What should the compression be for a Mercruiser 3.0?

 

[alldodge]

Your not helping

 

[achris]

You're not helping

:laugh::laugh::laugh::laugh:

 

[ronaldreagan]

New riser and manifold came in, getting ready to start the engine tomorrow.

Staring it out of the boat seems kind of tricky...

I've searched and found out how to connect the water line also know how to crank the engine.

How do I turn on the ignition with the motor out of the boat?

It's a 2004 with the electronic ignition.

 

[alldodge]

How to start

 

[ronaldreagan]

Success!!! It fired up and purred like a kitten.

 

[ronaldreagan]

Ugh.... Well I took the riser off to get ready to install engine and found a small amount for water at the bottom of the exhaust portion of the manifold. See picture.

Is this something that I should be worried about or is some water at the bottom of the exhaust manifold normal?

From the looks of it came through the exhaust when I was testing the engine out of the boat. . Just a reminder, these are new exhaust manifold and riser. Another note, I didn't run it long enough to get hot which would probably burn this off by the time the engine cools down.

 

[alldodge]

New mans and water in the man, there is a leak or something bad has happened

 

[Lou C]

When you say new mani/elbow, which manufacture? Not all are equal in quality. I would clean up the sealing surfaces and put a straight edge on them, you want them very flat & level with no low spots all around the sealing surface. When I checked my Barr aftermarket manifolds and elbows this way they were very good, could not fit a .001” feeler gauge in under the straight edge anywhere. That and use OE gaskets if these are aftermarket exhaust parts.

About your comp test results when I installed reman heads on my old 4.3 after a blown head gasket and water in cyl & oil incident with a warmed up engine and wide open throttle I got 165-170. So retest yours warmed up, it should improve. Even if they are a bit lower as long as it doesn’t burn a lot of oil and put out a lot of blow by you can just run it.
salt water use you must check & probably replace your exhaust more often at least every 5 seasons. That’s the whole cause of your problem here most likely. I am in the salt too replaced exhaust every 5/7 years never had water in a cyl from exhaust over 15 years of salt water use and mooring

 

[ronaldreagan]

When you say new mani/elbow, which manufacture? Not all are equal in quality. I would clean up the sealing surfaces and put a straight edge on them, you want them very flat & level with no low spots all around the sealing surface. When I checked my Barr aftermarket manifolds and elbows this way they were very good, could not fit a .001” feeler gauge in under the straight edge anywhere. That and use OE gaskets if these are aftermarket exhaust parts.

About your comp test results when I installed reman heads on my old 4.3 after a blown head gasket and water in cyl & oil incident with a warmed up engine and wide open throttle I got 165-170. So retest yours warmed up, it should improve. Even if they are a bit lower as long as it doesn’t burn a lot of oil and put out a lot of blow by you can just run it.
salt water use you must check & probably replace your exhaust more often at least every 5 seasons. That’s the whole cause of your problem here most likely. I am in the salt too replaced exhaust every 5/7 years never had water in a cyl from exhaust over 15 years of salt water use and mooring

The new manifold and riser are manufactured by Barr. Thanks for the feedback.

 

[ronaldreagan]

Went out on it yesterday and it really well. There was some "pinging" while getting on plane. Going to check the timing. Another suggestions to resolve pinging?

 

[alldodge]

If its actual pinging, then incorrect timing is what causes it.

 

[ronaldreagan]

Regarding the pinging, I check the timing per procedure in Manual 26 and it's pretty spot on, 1 degree ATDC.

Pulled the plugs, picture attached. What are your thoughts on how this looks?

 

[alldodge]

That one looks good, nice cream color

but how much idling was done before the plug was pulled?

 

[ronaldreagan]

That one looks good, nice cream color

but how much idling was done before the plug was pulled?

enough to warm the engine, about 10 minutes, I may have ran it at 1/4 throttle a few times in that period.

At idle with the distributor not jumpered, it's at 14 degrees BTDC which also lines up with the service manual. Likely not the ignition module.....

I drained the tank and put new fuel in it but maybe there was still some old fuel left.....?