Engine vibrating after water in engineoil

[juruca]

Hi everybody,

I'am not new on this forum(read alot already) but this is my first thread.

Last year (2020) i had a leaking exhaust manifold on starboard side.
So i got seawater in the engine oil.
I removed the starboard cilinderhead for inspection, looked pritty normal so rebuild again with new gasket, compression oke.
Drained the milky oil and flushed the engine 5 times with new oil and filter.
Now engine oil looks good, not milky.
I had two use exaust manifolds in stock(one piece) which i mounted after leak testing.
So after did timing adjustment to mercruiser specifications.
And is running fine after this but i have the follow problem: engine vibration at all rpms...
Not yet removed the drive to see if it stays vibrating.

Does anybody have an idea whats this can cause ?

Last week i go boating and discoverd this problem(vibrating) and after boating i allways drain the coolingwater after flushing with normal water and on both exhaust manifold very little water came out ??? normaly it was about 2 a 3 Liter.. so where did it go ?
Still the engine oil is clear.


Bayliner 1850 SE 4.3L EFI 1998
Engine cast code 090 with balancer.

 

[Scott Danforth]

first, welcome aboard

you have 1-piece engine killer manifolds on your 4.3? I would switch them to the new 2-piece.

there is no such thing as a good 1-piece manifold, AKA "Batwing" AKA "engine killer"

because of the casting process, and the core shift that happens with every cast product, the bat-wing manifolds often fail internally and take out the engines. this can happen within a few years, or they may last a 20. however they all fail.

regarding your rough running, could be any of the following:
damaged cylinder from leaking water
rusty valve from leaking water
spark plug not firing
spark plug wires crossed (wires on wrong plugs)
plugged injector
damaged cam lobe

use an IR temp gun find out which cylinder isnt firing, then investigate why

 

[Lou C]

I’d go back and check the compression again. Do these newer 4.3s have adjustable valve train or is it like the newer style net lash? I’m wondering if any valves are sticking due to the water ingestion. I had this when my head gaskets blew and leaked water into the cyl. I had one valve on each head that was sticking and caused rough running till the engine warmed up. Then each time after a cold start it would run rough till it warmed up. I replaced both cyl heads and replaced the one piece bat wings with the later style 2 piece exhaust. Do another comp test or better yet a cyl leak down test. Might need to get both cyl heads done. Barr Marine sells a conversion kit to replace the bat wings. I’d change them ASAP.

 

[juruca]

Thanks both for your quick response on my problem!

I heard before about the one piece exhaust.....

But the two piece exhaust can also corrode and start leaking or NOT ??

- What do you mean by demaged cylinder ??

- the performance of the engine is normal so spark must fire.

- spark plug wires can't be crossed(all different length) and seperated on each side.

- plugged injector is hard to believe because normal performance and i have seen them spraying at idle.

- do you have by damaged cam lobe compression ??

Tomorrow i go remove the drive and start again and measure the temperature on each cylinder.

- today i did a compression test, see attments. the leaking exhaust was number 6, starboard, transom side.

- Why you think i have to renew the backboard side headgasket ???

And picture after lifting the cylinderhead, dont know why cylinder 6 look wet... ??

Thanks in advance guys!

 

[Scott Danforth]

I’d go back and check the compression again. Do these newer 4.3s have adjustable valve train or is it like the newer style net lash?

1996 and later is fixed unless you convert to adjustable

 

[Lou C]

Normal compression is 150-160 on these engines so your # 6 is low at 120 and the cyl head gasket looks blown to me…dark around the left side of the cylinder.
Yes the 2 piece system can corrode and leak but if in salt water you have to replace them on a regular basis like every 5-7 years. I had the OMC bat wings on my V6 and changed them that often and they never failed me. But the Merc ones were a known bad design they discontinued them after 3 years because they couldn’t get consistent wall thickness. Fix your engine (take both heads to a machine shop to get checked out and redone) and toss those bat wings and start with a new set of 2 piece Merc or Barr aftermarket manifolds.

 

[Lou C]

1996 and later is fixed unless you convert to adjustable

That’s what I thought