Honda 40 - gas in oil

[PlanB]

I have a Honda 1999 - 40 hp outboard that is getting gas in the oil. The dealer suggests rebuildin the carbs to the tune of $300 - $400.<br />The engine runs fine but the oil level will get well above the full mark on the dipstick.<br /><br />Any suggestions would be appreciated.

 

[DJ]

Re: Honda 40 - gas in oil

PlanB,<br /><br />You're leaking gas into the oil, or diluting it with a rich mixture.<br /><br />I suspect the dealer is right.<br /><br />This needs to be addressed right away. Your lubrication oil is not effective if diluted.

 

[Walker]

Re: Honda 40 - gas in oil

How old is the motor and how many hours are on it. I read about a lot of the Honda 4 stroke doing this until they got broke in. Do a search on this BB and you'll probably find other threads about the same thing.

 

[PlanB]

Re: Honda 40 - gas in oil

The motor is 3 years old. Did fine for the first two seasons. Just started this last season (one month out of warranty.

 

[Skinnywater]

Re: Honda 40 - gas in oil

Hello PlanB,<br />You wrote your "motor runs fine". Does it start well to? Does it start well after running for a while then sitting after a hotsoak? Does it smell like it is running rich at all?<br /><br />If you aren't having any start, run or flooding problems I'm not so sure I agree with your dealers diagnosis.<br /><br />I've experienced oil in the gas from carbs many times before but it always came with one heck of a run/start/rich run problem. <br /><br />With your engine off, your sidedraft carbs would drain through the silencer (air induction) before they would leak into the intake manifold and it has a drain tube through the bottom of the cowl for that purpose. <br /><br />I'd have a hard look at that fuel pump before I'd have those carbs disturbed. Especially if you weren't having ANY of the above symptoms.<br /><br />Please let us know what your/thier actual finding was.

 

[hondon]

Re: Honda 40 - gas in oil

Let me fly this one by you.You have had an pretty cold winter out there this year.Do you do alot of trolling in that cold water?These engines can make oil in those circumstances.A leaking fuel pump will also add fuel to your oil but will let you know of its failure by obvious perfomance let downs.Carb needle and seat problems will be evident if the carbs are flooding over when you pump the primer bulb.It's real easy for an engine to break itself lean but real hard to break itself rich, and there are only a few things that will cause it on this engine.

 

[zzzzz]

Re: Honda 40 - gas in oil

i've heard of that problem a couple of times from our customers.our other store does our service work and they indicate that it has always come down to the fuel pump.

 

[PlanB]

Re: Honda 40 - gas in oil

bobq - do you know if the fuel pump has a replaceable diaphram?

 

[zzzzz]

Re: Honda 40 - gas in oil

sorry-no replaceable diaphragm-pump prox $83

 

[John Hzzzzz]

Re: Honda 40 - gas in oil

I have been through your problem only recently. I have been lucky as I have a cat with two hulls and two honda 50hp 4 strokes. Because of the two motors I have been able to do a bit of swapping of components across to pinpoint the problem. After extensive swapping I found that the problem was a stuck open thermostat. This may sound strange but trust me, this was causing the problem. I have put this to some knowledgeable mechanics who say that is possible that the engine was not heating up to the optimal operating temperature whereby allowing unburnt fuel to enter the sump from the cylinders.<br /><br />By the way my motors are 5 years old and have been running perfectly for 700 hours<br /><br />Hope this is the problem so that you can easily trace it

 

[dbajaer]

Re: Honda 40 - gas in oil

I am having the same problem, after 8 hours of running and trolling I found the oil to be almost one quart too high, changed the oil and then tried another day of fishing, my BF45A had the oil level up another quart! I have taken the fuel pump off and tried to pump it by hand while the lines were connected, no noticible fuel comming out of the drive area. I remove the pump from the lines and tried to bench test, still not conclusive, blew air against the diaphram with soap on top, still not signs of pin holes or bubbles. I have noticed only one differnce in the running of the motor, when I backed off the trailor it died, several times, then ran fine and seemed to perform as usual, 5,000 rpm with three passengers in the boat, never missed or had problems starting hot etc. I am a bit concerned, ordered a new pump, will install it, I will re-post after trying it with the new pump!