Please help with Honda water in oil problem

Brede

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Joined
Feb 17, 2009
Messages
5
Hi, I have an older (prob early 80's) 10HP 4-stroke Honda outboard. The motor started to get water in the oil, and after replacing all the gaskets and seals, I thought I had solved the problem. I used it for about a dozen times, and then let a friend borrow it (which I will not ever do again) He proceeded to smash the thing into a submerged rock at full speed. After some inspection, I discovered that the timing had jumped a couple of teeth, but there was no actual damage. I took it all apart, check all the valves, none of them were bent, they all looked perfect. I put it all back together with all new gaskets and seals, and after a couple times out, I check the oil and it had leaked water again. So I have a couple of problems that I am hoping I can get some help with. First of all I am wondering if any of you guys have ever had any problems using RTV adhesive. I used it to hold the o-rings and some of the gaskets in place while putting things together, is it possible that the RTV is causing the leaking? Possible heating up and losing adhesion from the metal allowing water to leak into the oil. Second, if that isn't the problem, is there anyway to pinpoint the water leak other than just taking it all apart? I would like to get an idea of where to look before I just start tear things off. Can I plug up the water system and compress it with air to possible hear where the leak is? I was told that there are a couple problem areas with this motor, i.e. the plastic piece that holds the dipstick, where water also runs through can crack. And something about a place in the head that water and oil are only separated by a rubber o-ring. But are there any other areas that someone knows of? I will also say that after its abrupt meeting with the rock it doesn't seem to be as powerful. Now I know that part of it is prob a slight bend in the prop. There is one little bend at the end of one of the blades, but I don't think it is big enough to cause in the amount of power lose I am experiencing, I have had a bent prop before with this motor, and it was a much larger bend, and it didn't cause the same amount of power loss. Thank you in advance for you help, this has been a frustrating issue for me.
 

Silvertip

Supreme Mariner
Joined
Sep 22, 2003
Messages
28,771
Re: Please help with Honda water in oil problem

RTV is very slippery so it should not be used on O-rings since these are used in areas where any fluid trying to get through them compresses the ring causing it to expand outward creating a tighter seal. If you slather RTV on them you prevent them from working properly. Aviation form-a-gasket is a far better sealant choice for flat gaskets. O-rings should not need a sealant. Passages that are under oil pressure which may be in the 40 - 60 PSI range need a good seal. RTV in various forumlations are used for items like valve cover seals or other areas not subjected to pressure. If you are using RTV around oil pressure passages that may indeed be your problem. Again, if a sealant is called for, Aviation form-a-gasket would probably work although Honda probably recommends a similar product with their name on it and costing twice as much.
 

Brede

Recruit
Joined
Feb 17, 2009
Messages
5
Re: Please help with Honda water in oil problem

Thanks for the help...I am going to replace the o-rings and gaskets (again) without the RTV at the o-ring and see. I have to look at the manual to see what, if any, sealant they recommend.
 

billshef

Recruit
Joined
Nov 11, 2004
Messages
4
Re: Please help with Honda water in oil problem

Just saw your post.....Replace the plastic part at the dipstick with a metal one. The plastic ones warp with heat....
 
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