engine leaving a trail of oil

[mikegj]

Hi all
I have a 1979 johnosn javlin 100 hp. Ive used this engine about 10 hours since my purchase. yesterday I noticed a trail of oil as I was heading out it is engine oil (not gear case oil). rpm's 800 idle 5300 WOT, engine temp 130 F,water press 5psi idle 18 psi WOT, the engine makes no odd noises,but has started to miss at idle or die. What do I check for, or do to fix this?

 

[jtexas]

Re: engine leaving a trail of oil

Watch the back side of the fuel pump while it's idling, or while somebody pumps the primer bulb - if fuel drips out, it means the diaphram is perforated - easy fix, order a rebuild kit from iboats. The bad idle could be related to this.

Look at the bottom of the back side of the airbox cover, should be a nipple with a short hose leading to the crankcase - that hose comes off there pretty easy, just shove it back on - try to secure it with a ziptie if you can. Does not affect idle.

Does the fuel line hold pressure? When it dies, is the bulb still firm?

Cylinder drop test: engine idling on muffs, pull then replace each spark plug wire, one at a time. use a plastic or insulated tool. if engine RPMs don't decrease noticeably, that cylinder's not making power.

Spark test: set your tester (couple bucks at auto parts store) for 7/16" and look for strong blue spark while turning the engine over.

Compression test - look for even compression across all cylinders.

good compression, spark and fuel pressure, time for carb rebuild.

 

[F_R]

Re: engine leaving a trail of oil

Hi all
I have a 1979 johnosn javlin 100 hp. Ive used this engine about 10 hours since my purchase. yesterday I noticed a trail of oil as I was heading out it is engine oil (not gear case oil). rpm's 800 idle 5300 WOT, engine temp 130 F,water press 5psi idle 18 psi WOT, the engine makes no odd noises,but has started to miss at idle or die. What do I check for, or do to fix this?

Just how much oil is it leaving? You must understand that the oil that you put in the gas is not all burned. Some of it is burned (smoke) and some of it goes right through the engine and out the exhaust. Especially at slower speeds, although your model is relativly efficient as technology at the time allowed. If it were to ALL burn 100%, you wouldn't be getting any cylinder lubrication.

Now, misfiring adds to the unburned fuel being discharged. Fix that.

All this is the cause of the controversy concerning two-strokes and the environment. If you are concerned about the environmental impact, use 100% synthetic TC-W3 outboard oil, it is claimed to be bio-degradeable.

 

[Theoutdoorsman]

Re: engine leaving a trail of oil

One last note.......... Check for a leaky trim cylinder(s) if you have tilt and trim installed on the outboard. If leaking even a little, they can and will leave a horrible looking oil slick behind the boat. This has absoulutely nothing to do with the miss your experiencing though. After testing compression, spark, and fuel, you might consider a good decarb, should everything check out ok. Those crossflows tend to build up carbon deposits really bad. I rebuilt my '79 140hp two years ago due to carbon deposits. Had I performed an annual decarb like I should have, it would likely have lasted a good long while. Another concern is the WOT rpm's. You should consider getting those up to 5600-5800 rpm's. You might get by with some simple setup tweaks to obtain the extra 300 or so rpm's. But that's a whole new topic better dealt with after you've corrected the problems listed here. Just thought I'd give you some more food for thought.......... ;-) ......... Good luck!............. ALAN

 

[mikegj]

Re: engine leaving a trail of oil

Thanks for all the pointers I'll get to it on sat. It is not the T&T leaking, its eng oil and a lot of it. The exhaust holes on the top of the midsection are dripping oil and there is a lot of sheen on the water following the boat, once I speed up I cant tell if it is still dumping or not cause its comming out the prop.
i will give results on sat.

 

[mikegj]

Re: engine leaving a trail of oil

UPDATE finally got time to look at engine today. First thing I did was to pump the fuel bulb looked in the water and saw a sheen. Upon further inspection found the fuel hoses dry rotted and clamped with zip ties. dealer said all hoses were replaced so I never gave it a second thought. Will replace tomorrow and follow up with results.

 

[mikegj]

Re: engine leaving a trail of oil

OK
replaced all the fuel hoses pumped the fuel bulb and now fuel dumps out of the bottom carbs. what do I do next

 

[flipjoe]

Re: engine leaving a trail of oil

carb rebuild

 

[jtexas]

Re: engine leaving a trail of oil

carb rebuild

yup. If you want to maintain this motor yourself (and there's no good reason not to), I highly recommend the factory service manual. He who repairs his own engine without a manual has a fool for a mechanic.


FYI, the zip ties are factory spec. they hold fine until the fuel line rots.

 

[mikegj]

Re: engine leaving a trail of oil

replaced carb float needle valve & seat reinstalled pumped fuel bulb all ok started engine runs perfect. THANKS ALL

 

[Theoutdoorsman]

Re: engine leaving a trail of oil

Now that you have everything as it should be, you might want to seriously consider a "decarb". Too, you may wish to post another question regarding those rpm's at WOT. Some photo's of the outboard hanging straight down on the transom would be most helpful for your new thread. Some folks will be particularly interested in your AV plate in relation to the bottom of your hull. You'll be amazed at what you might learn. Glad you got her fixed!!! Congrats!!!.............. ALAN


Here's the decarb link......... http://forums.iboats.com/showthread.php?t=158076