Gas in the oil?

LightningBob

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Mar 14, 2021
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Long story

I removed an old mercruiser 228 and bought a used 228R 1984 because the older mercruiser had a busted water jacket on the block.

with the “new” engine in my garage I took the time to put new seals all around it. Pulled the heads and lapped the valves. New head gaskets, new valve seals, new intake gasket, new oil pan gasket probably a lot more I’m just forgetting to post. I didn’t replace the timing chain, camshaft, crank or bearings on either of those. New oil, and like I said, a lot of other stuff I’m probably drawing blank on.
after the rebuild I ran the engine on a stand and let it burn through about 5 gallons of gas just to prove to myself that it was a good engine before I dropped it in the boat.
From the old engine, I robbed the motor mounts and the flywheel cover so it would all bolt up to the old “pre-alpha” as I see it called on most forums.

anyway, now to the fun stuff:
I was struggling to get the quadrajet to do anything over a few thousand RPMs. I tried monkeying with it and I shouldn’t have because no improvement was made. A friend at church said to just junk those quadrajets and get something more reliable. I decided to rob the carburetor off the other engine I have. It was probably in even worse shape.
I then moved to draining the gas tanks and put fresh in them.
that seemed to help with the idle issue but as soon as I accelerated, it just took a dump and died.
I’m pretty sure the engine was “flooding” and was struggling to burn all the fuel the carb was dumping, I let the engine sit overnight undisturbed and the next morning I tried to run it again. This time I noticed a brownish gray junk spraying out of the hoses on the flame arrestor on top of the carburetor. (I think it was brown/gray im color blind).
I pulled the hoses off of the valve covers that go to the flame arrestor and out of the holes in the valve cover, engine running, that junk was coming out.
im 99% sure it was gas mixed with engine oil, it smelled like gas but looked like oil.
My father stopped by with a coworker today on lunch break and they sent a video to a local mechanic.
he said that it’s likely the float was stuck inside the carburetor and the engine flooded.
I broke down and went to a performance store in town and I got a new edelbrock carburetor that was suggested to me..

does this diagnosis from a local mechanic sound correct?
what exactly is the fix? Drain the oil and put fresh in it?
how can I stop this in the future?

im pretty lost with this one. Regardless if it was gas and oil mix why would anything be spraying out of those valve cover holes, they have some sort of windage tray on the internal side of those holes, I can’t see why it would matter if it’s a mixture of fuel and oil or just oil... why is it coming out of there. How Do Stop
Thanks always,
Lightningbob
 

nola mike

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Apr 22, 2009
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5,362
.

does this diagnosis from a local mechanic sound correct?
what exactly is the fix? Drain the oil and put fresh in it?
how can I stop this in the future?
1. Yes
2. Yes
3. New carb should fix it
im pretty lost with this one. Regardless if it was gas and oil mix why would anything be spraying out of those valve cover holes, they have some sort of windage tray on the internal side of those holes, I can’t see why it would matter if it’s a mixture of fuel and oil or just oil... why is it coming out of there. How Do Stop
Thanks always,
Lightningbob
I can see that, but you'd need a crap ton of gas getting past those rings and into the pan. I can more see that that's water mixed with the oil though
 

LightningBob

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Mar 14, 2021
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26
1. Yes
2. Yes
3. New carb should fix it

I can see that, but you'd need a crap ton of gas getting past those rings and into the pan. I can more see that that's water mixed with the oil though
Thanks,
I will pump the contents out of the oil pan in the morning and put fresh oil in it
I didn’t know this was so well known

I appreciate it,
Lightningbob
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
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is the clear hose running from the fuel pump to the carb full of fuel, if so, your fuel pump let loose
 

LightningBob

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Mar 14, 2021
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26
1. Yes
2. Yes
3. New carb should fix it

I can see that, but you'd need a crap ton of gas getting past those rings and into the pan. I can more see that that's water mixed with the oil though
Just to add:
It’s a closed cooling system, not that antifreeze couldn’t be getting into the oil but I think it’s probably not the culprit. And I’ve just been testing it for 2-3 minutes at a time without running it on the water hose and “earmuffs”
The engine or manifolds/risers haven’t been hot to the touch

I’ll reply with what I find tomorrow
 

LightningBob

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Mar 14, 2021
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is the clear hose running from the fuel pump to the carb full of fuel, if so, your fuel pump let loose
I will check this tomorrow for sure.
which makes me think:

I have some performance Chevy stuff laying around. Say a man had an electric fuel pump and a regulator laying around on a shelf, would this work in a marine application?
 

Paintman1960

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Apr 21, 2021
Messages
153
I will check this tomorrow for sure.
which makes me think:

I have some performance Chevy stuff laying around. Say a man had an electric fuel pump and a regulator laying around on a shelf, would this work in a marine
 
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nola mike

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And I’ve just been testing it for 2-3 minutes at a time without running it on the water hose and “earmuffs”
The engine or manifolds/risers haven’t been hot to the touch

I’ll reply with what I find tomorrow
3 minutes without water? You need a new impeller at least, if you're lucky.
 

LightningBob

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Thanks for the info

I’m not sure what brand the fuel pump is I have but I’m almost positive I have a Holley regulator.

do you think it would be ok to test with And use for a day or two on the water while the new mechanical pump comes in the mail?
 

Paintman1960

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Yea, Im sure yer impeller is toast after 20 sec's, let alone a Minute ! or 3
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
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Messages
49,540
I will check this tomorrow for sure.
which makes me think:

I have some performance Chevy stuff laying around. Say a man had an electric fuel pump and a regulator laying around on a shelf, would this work in a marine application?
Only if its marine. It has to have the SAE 1171 certification

I would never use an electric fuel pump if a mechanical is an option

A $45 mechanical pump will outlast a $90. Marine electric pump, a $20 oil pressure switch and the relay and wiring needed
 
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