www.iFourWinns.com

FINAL THOUGHTS: We put about 8-hours on the meter. Some of it with a light load (2-persons) and some with heavy load (7-persons). Out of the hole with a light load took maybe 5-seconds. Heavy load a lot longer (20+) but if I moved people towards the front of the cockpit it took less. Ran as high as 3800-rpm (light load)(about 35mph) in mostly flat water, but backed off as wakes approached. Heavy load at about 3200-rpm and 25mph. No engine hiccups, smell, loss of power. The throttle was fully responsive. Engine Temp was steady between 150 and 170.

The mechanic (who is now a friend, it seems, i have seen him so much) now believes the oil issue was the culprit. He called it a "cancer" slowly getting worse and then reaching a tipping point forcing the engine computer to run lean. Pretty good detective work.

For those who have followed this journey (Lou?) here are a few pix of the sea-trial in the San Juan Islands, Washington.
http://www.sunriver-rental.info/fourwinns/engine1.jpg
http://www.sunriver-rental.info/fourwinns/engine2.jpg
http://www.sunriver-rental.info/fourwinns/engine3.jpg
http://www.sunriver-rental.info/fourwinns/matia.jpg
http://www.sunriver-rental.info/fourwinns/wake.jpg
http://www.sunriver-rental.info/fourwinns/sunset.jpg
http://www.sunriver-rental.info/fourwinns/boat.jpg
http://www.sunriver-rental.info/fourwinns/boat2.jpg

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Four Winns 1996 Sundowner 205
5.0fi/SX engine (Volvo Penta)

Great pix and glad to see the problem solved! That’s a real mechanic!

also since this so got my curiosity up, I was trying to really understand how oil got into the intake tract, looking at pix of that lower EFI manifold for the Ford 5.0. There is no bottom plate to leak as in the Chrysler EFI manifold used on the old 318/360 Magnum V8s. However, if the intake gaskets failed at the lower edge under high manifold conditions like idle and decelleration, I can see how oil would get sucked right up to where the injectors were from the cam valley below the intake.

I do look at this and am happy I still have a simple cheap to repair by myself carbed engine. I've been getting good at rebuilding the Quadrajet. I've had it apart twice for a rebuild and some tweaking this spring and its the best its ever been. Rebuild kits are like $45, a fuel pump is like $85.

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88 Four Winns 200 Horizon
4.3 OMC Cobra-4bbl
2002 Walker Bay 10/2012 Suzuki 2.5
2008 Walker Bay 8

1998 Jeep Grand Cherokee 4.0/Selectrac
2007 Jeep Grand Cherokee 5.7 Hemi/Quadradrive II

Interesting to read this entire thread, as I come here tonight to find help with MY problem

Did I read this correct: the OP's problem was solved by correcting the engine oil level, as it was grossly overfilled? Or was it a leaking intake gasket??

Having a similar problem and trying to figure it out....

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1997 Four Winns Vista 278
T - 4.3l EFI
Kohler 4esz Genset
379 hours as of 8/8/21

Intake gasket was main cause and high oil level probably exacerbated it.

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88 Four Winns 200 Horizon
4.3 OMC Cobra-4bbl
2002 Walker Bay 10/2012 Suzuki 2.5
2008 Walker Bay 8

1998 Jeep Grand Cherokee 4.0/Selectrac
2007 Jeep Grand Cherokee 5.7 Hemi/Quadradrive II

I asked my mechanic to give me the readers digest review of what he thinks happened:

"Too much oil in the crankcase, means when the pistons travel downward there is no room for air to escape, so it pressurizes the oil, pushing it out through the crankcase breather into the flame arrester, and into the air intake."

I would love to find the tech who put all that oil in there. Basically twice as much as needed. I have my suspicions.

I hope this thread helps someone with a like-problem.

Mark

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Four Winns 1996 Sundowner 205
5.0fi/SX engine (Volvo Penta)

Great follow up and what comes out of this is that sometimes an apparently complex problem has a simple cause. It also highlights how important it is to check work done by others even simple things like oil changes! I’ve been doing my own since 1972….

_________________
88 Four Winns 200 Horizon
4.3 OMC Cobra-4bbl
2002 Walker Bay 10/2012 Suzuki 2.5
2008 Walker Bay 8

1998 Jeep Grand Cherokee 4.0/Selectrac
2007 Jeep Grand Cherokee 5.7 Hemi/Quadradrive II