oil, gas slick when running
Printed From: CorrectCraftFan.com
Category: Repairs and Maintenance
Forum Name: Engine Repair
Forum Discription: Engine problems and solutions
URL: http://www.CorrectCraftFan.com/forum/forum_posts.asp?TID=43167
Printed Date: May-05-2024 at 2:45pm
Topic: oil, gas slick when running
Posted By: dpkumph
Subject: oil, gas slick when running
Date Posted: July-16-2018 at 11:35am
I have a 1984 - 2001. Owned it for 6 years, Great boat, great condition, runs very well. 1200 hours on the motor. Fresh water only, used in Winnipesaukee, NH - early mornings for skiing. This season I am noticing an oil slick (or gas, tranny fluid) in the water behind the boat when the motor is running - presumably from the exhaust - and it seems to be getting worse. I have added a quart of oil which is typical for a season for me. Oil on the dipstick looks clean, no water or cloudiness, Tranny fluid is also clean, correct color, no water / cloudiness. all 8 plugs look clean, not fouled or wet - no gas smell. Advice from local mechanics is to just run it, which makes sense. That said, does anyone have any advice on what this might be and ways to diagnose it? Thank you very much in advance for your time.
Doug K
New Hampshire
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Replies:
Posted By: MACS81SN
Date Posted: July-16-2018 at 11:50am
When I’ve seen this, it’s usually the choke butterfly only partially open or carb in need of rebuilding. Has the carb ever been rebuilt? If not it’s long over due.
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Mark
1999 -SN - 502 Python
1981 - SN Owned 33 years - Sold
1968 - Mustang - Sold
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Posted By: dpkumph
Date Posted: July-16-2018 at 12:05pm
Thank you,
Yes, the carb was rebuilt 3 years ago. This would mean its fuel in the water, correct? A buddy of mine said it was fuel when we were skiing a couple weeks ago because of how it "popped" / appeared volatile when it was on the surface.
what is the best way to check the choke butterfly, just pull the flame arrester and look ?
This would be much better news than oil. Is it possible to post video clips?
thanks
Doug
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Posted By: 8122pbrainard
Date Posted: July-16-2018 at 12:17pm
Doug,
Keep an eye on the trans fluid level. You may have a leak in the trans cooler. It just takes a drop of oil on water to make the slick/sheen especially with ATF since it has so much detergent/surfactant in it.
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/diaries/details.asp?ID=1622" rel="nofollow -
54 Atom
/diaries/details.asp?ID=2179" rel="nofollow - 77 Tique
64 X55 Dunphy
Keep it original, Pete
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Posted By: dpkumph
Date Posted: July-16-2018 at 3:20pm
thanks 8122pbrainard -
I've been checking the tranny fluid level - wondering if this is a possible source. I had the tranny rebuilt 2 years ago, but did not change the cooler, which I presume is original and possibly corroded...would water also go into the trans fluid or not due to it being on the suction (low pressure) side of the raw water pump?
So far it looks like the level is correct and fluid is still red and clear - but this could easily be a slow leak. Thanks for the input,
Doug
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Posted By: dpkumph
Date Posted: July-16-2018 at 3:31pm
Pete,
sorry, I should have thought more, but I was excited about the prospect of my engine not being broken...your suggestion would explain why my engine is running very well, plugs not fouled, etc. Seems like I could bypass the cooler to trouble shoot this...are these easy to test for leaks? seems like it should be. any follow up info is very much appreciated.
thanks
Doug
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Posted By: 8122pbrainard
Date Posted: July-16-2018 at 3:39pm
Doug,
Correct that since the cooler is on the suction side of the RWP, ATF can be sucked into the cooling. Water can also get into the trans from when the trans cools, the trans vent isn't the best and then there's a partial vacuum created. Yes, keep an eye on both the trans level and the color. It takes a pretty decent amount of water in the ATF to turn it pink. My understanding is the ATF has additives that absorb some water.
You could also pull the cooler, rig up some fittings, apply some air pressure and with the cooler under water, run a pressure check looking for bubbles.
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/diaries/details.asp?ID=1622" rel="nofollow -
54 Atom
/diaries/details.asp?ID=2179" rel="nofollow - 77 Tique
64 X55 Dunphy
Keep it original, Pete
<
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Posted By: dpkumph
Date Posted: July-16-2018 at 6:15pm
Update for the record: I pulled the hose off the bottom of the raw water pump - (after the cooler and before the RWP) and collected the water in a clean quart plastic container. I clearly saw a sheen on the top of the water. I also pulled the top hose off the cooler and was able to look into the cooler, and see a sheen on top of the water there too. I was advised not to run the motor with the cooler bypassed so I didn't. I had this tranny rebuilt two years ago, not worth risking damaging it. Having seen the same sheen in my samples, I ordered a new tranny cooler from my local shop - thanks to Craig at NECC Boats. I hope to install it next Saturday morning and be skiing again soon. Thank you for the input and help. Pete, although I am not 100% sure, I am pretty hopeful and unstuck for now - Thank you.
Doug
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