Gas in oil ... pump replacement?

Dhopper71

Seaman
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Jun 12, 2011
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70
I'm finally getting my '74 Mercruiser 140 3.0L running well. Spent a lot of time tinkering and tuning, but still have this issue present. I have changed the oil now a few times, but when I pull the dipstick, it still looks a little diluted and smells like gas. The fuel pump is the old Carter mechanical unit with no third line up to the carb. If the diaphram goes on this unit, does it just dump into the crackcase? How dangerous is it if there's gas in the oil? Is there another way it could be getting in the oil? Bad rings? Wouldn't compression be really low for that? I'll run another test to check and post the numbers.

I'm ok with replacing the pump, but would rather put in an updated unit if possible. Can anyone tell me from experience if these can be updated or do I have to order the more expensive old type again?
 

Don S

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Re: Gas in oil ... pump replacement?

Replace the pump.
 

Dhopper71

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Re: Gas in oil ... pump replacement?

Replace the pump.

well, i was thinking that. any help with which pump i could use instead of the old carter pump? a newer style marine mechanical pump with the sight tube running to the carb?
 

Bondo

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Re: Gas in oil ... pump replacement?

well, i was thinking that. any help with which pump i could use instead of the old carter pump? a newer style marine mechanical pump with the sight tube running to the carb?

Ayuh,... ya can update it, but you'll have to re-engineer the fuel lines, 'n whatnots to do it....

Only a copy of the original will be plug, 'n play...

Hate ta think you'd get another 40 Years outa another 1....
 

Dhopper71

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Jun 12, 2011
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Re: Gas in oil ... pump replacement?

Ayuh,... ya can update it, but you'll have to re-engineer the fuel lines, 'n whatnots to do it....

Only a copy of the original will be plug, 'n play...

Hate ta think you'd get another 40 Years outa another 1....

'Nuf said. No reason to reinvent the wheel if it rolls for that long. Thanks.
 

Dhopper71

Seaman
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Jun 12, 2011
Messages
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Re: Gas in oil ... pump replacement?

Ok guys. Need a bit more help.

I just found a great looking replacement pump at my local shop for basically nothing. I found a new internal filter and gasket at napa for just a few bucks. My question is about the safety line that runs to the carb or flame arrestor. My old pump did not have this feature, but this pump does.

How should I run that line? How does it connect to the carb? Should I use standard marine rubber fuel line or metal line? How about marine grade Tygon fuel tubing? Just want to make sure I utilize this feature correctly and safely.

Thanks again!
 

Dhopper71

Seaman
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Jun 12, 2011
Messages
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Re: Gas in oil ... pump replacement?

UPDATE:

Check out my slideshow of removing the old fuel pump and setting up the replacement.

I also drained the oil, then flushed with 1 gal diesel/1 qt oil - run for 2 min at lowest idle - drained completely and removed/replaced oil filter. Tmrw I get everything all back together and with any luck it will start. I'm running a new compression test as well, and put in new points, rotor, condensor, and cap.

Wish me luck!!

http://s36.photobucket.com/albums/e10/ashlea30/?action=view&current=d342c874.pbw
 

Dhopper71

Seaman
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Jun 12, 2011
Messages
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Re: Gas in oil ... pump replacement?

Update:

I got the replacement pump installed today. Looks like everything is working great. (knock on wood)

I refilled the oil after it sat empty overnight following the flush yesterday. After installing the pump and new dump line, I put in the new cap, rotor, and points. I immediately knew something was different, when I slowly cranked it over that first time .... and it fired up instantly and idled right off the bat at about 600 rpm. I hadn't heard this thing start that fast since I brought it home. After a few tweaks of the idle screws it purrs at 900 on the muffs. I'll reset it on the water to make sure I keep it at 800. I checked the dwell and it is at 30. I'm still working on getting the timing set. I couldn't get any wrench in to loosen the dist' bolt. Sounds like it must be pretty darn close the way it's purring, but it still needs to be set the right way.

After running it for about 15 minutes at idle and low 1200 rpms, it leveled at 140* operating temp.. I've checked the oil several times - while it was hot and over the last 20 minutes while it cools down. Looks like all traces of water moisture and gasoline are gone from the engine oil. Now I just have to pray that it stays that way!

Thank you all for your help. I can't wait to get this on the water again this week, and finally get the family out on it!! Wish us luck. Watch out Pickwick Lake, TN.

c18047ba.jpg
1225a463.jpg

 

1987sylvanoffshore

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Apr 7, 2010
Messages
46
Re: Gas in oil ... pump replacement?

I could be wrong but I don't think your plug wires are in the correct order.
 

Dhopper71

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Jun 12, 2011
Messages
70
Re: Gas in oil ... pump replacement?

I could be wrong but I don't think your plug wires are in the correct order.

Should be 1-3-4-2 right ?!?! LOL! Thought I posted the other video!! Thanks for catching that for me. Took me a few minutes after I hooked it up that way to figure out why the idle sounded funny.
 
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