Four Stroke Gaskets

[AGENT 37]

I have just rebuilt my 1999 F100. After reassembling it I have an oil leak running down the driveshaft and splattering out onto the mounting bracket and also have water getting into the oil at higher RPMs. If I let it idle on the muffs for abouT a half hour the oil starts to clear up. When I was reassembling it the manual called for sealant on the crank case mating halves but as far a I could tell only indicated oil on the crank seal/oil ring. So I didn't put any sealant around the outside of the rubber, just on the metal to metal surfaces. I have a feeling that might be where the oil leak is coming from. Any opinions on sealing that up? Any suggestions for the water leak? I had the cylinder head welded and milled down, installed new gaskets, and followed specified torque patterns and values. I pulled the power head and found a little bit of material that I missed, cleaned it and applied a gasket maker to the gasket and reinstalled it without much improvement. I took it back apart and have two fresh gaskets on hand. I would appreciate any tips to help me get this thing fixed. The manual referred to applying a coat of metallic paint to the gasket if the head had un-correctable warpage to help fill in gaps. I'd like to hear ideas either way. Personally I've always gone with what the book says as the standard methods and manufacturer recommendations.

 

[rodbolt]

Re: Four Stroke Gaskets

if you suspect a head gasket leak into the cooling system a leakdown test may aid in finding it. I place a trashbag over the exhaust/propshaft,plug off the telltale and listen fir air out of the idle relief.
on the oil leak, it could be the oil pump seals/orings leaking.

 

[mokaction]

Re: Four Stroke Gaskets

Question?? did you have the cylinder re-sleeved?? and if so who did it..

Larry

 

[AGENT 37]

Re: Four Stroke Gaskets

I didn't have to do any work to the cyliders other than honing them for the new rings that I installed. I replaced the crank, a connecting rod and piston assembly, all of the rod sleeve bearings, and had the cylinder head welded and milled .003/in. due to corrosion. The head was the only part that was corroded, the block was clean and solid. I buffed out the surfaces and detected no cracks with a good v/i. I replaced all of the gaskets and followed specs.

 

[AGENT 37]

Re: Four Stroke Gaskets

I know that it has a leak; cooling into the lube system. Oil gets milky when running at high RPM but cooks off most of the water when I let it idle for about a half hour; the oil starts to clear and turn dark again. The oil level is not changing so I wouldn't say it's a major/ high volume leak, but a leak is a leak. I don't think that a leak down test will help me locate the leak. I was initially suspecting a leak at the pan gasket because I missed some old material when I reinstalled the powerhead with a new gasket, it was dark out. I pulled the power head and cleaned off the surfaces. I took the used gasket (new when I reassembled motor) and removed all of the factory adhesive and sprayed on a 3m coat and reassembled it and still had the leak. Since it's a crush style gasket I'm not suprised. I pulled the cylinder head just to see if one of the welds gave way or the head cracked and it all looked fine. When I initially built up the motor I installed the head gasket with a coat of yamaha factory metallic paint to add an extra even volume to it just in case there was an inperfection to be filled. I reinstalled the head with a new head gasket, without paint this time. I have a new pan gasket that I'll install when the power head goes back on, I plan to buff the surfaces bright and clean this time before I put it together.

I bought a set of new o-rings for the oil pump and will install them. I did pull the pump and disassemble it to check and didn't replace the o-rings. I know, I know. We replace them as standard practice when we inspect the mag plugs and chip detectors on our aircraft. I didn't have them on hand and wasn't patient enough to wait. The dumb power head gasket set that I paid $300 bucks for had a lot of extras that aren't used for my motor but didn't have seals for the oil pump or the fuel pumps.

 

[AGENT 37]

Re: Four Stroke Gaskets

Should the crank case oil seals (top and bottom or the crank shaft) have sealant on the outer edges? The manuals indicate oil on the seals, presumably the inside, but don't indicate sealant on the outside. I didn't use it on the basis that I'd expect the rubber to create a seal with the crank case when it is torqued.

 

[AGENT 37]

Re: Four Stroke Gaskets

The engine is running excellent. I've put four hours on it but the water is showing now that to the stage of opening it up. I changed the oil three times to see if it changes. But I'm not running it anymore because the leak didn't improve when I pulled and reinstalled the power head. I'll finish putting it back together when I get home in a couple of weeks with the new gaskets and seals and see what happens.
Flush your motors. The previous owner did not and it took it's toll. When I got the motor the oil was normal, obviously used. It sat for a few months after it was pulled from the boat due to rough running and I assume that's when the head was done in as the O2 was really able to get to it in the salty environment of the un-flushed water passages. I got it running with a fuel system overhaul and changed the fluids. Right away it was spitting out chunks from the overboard, big enough chunks to clog the nipple. It was idling good though so I took it for a test run. When I put a little bit of throttle to it I could hear the horrifying sound of the connecting rod that wasn't evident on the ears at idle. The oil was milky too. I know that the rod was wrecked before the oil contamination. It was the #2 with the rev limiter and the engine was run hard on too big of a boat.

 

[AGENT 37]

Re: Four Stroke Gaskets

I put it all back together with new seals and gaskets after buffing the surfaces bright. Ran it and still got milky oil. The external oil leak seems to be stopped though. The weld broke on the ptt actuator because the joints are all rusted up. When it broke the actuator seized, so I took the hyd. tilt trim assembly off. My blood is boiling. I'm done with this p.o.c. What a disappointment to put so much time, money, and effort into something and wind up here.

 

[mokaction]

Re: Four Stroke Gaskets

Man I feel for you. Been in situations like that too.. If worse goes to worse you can always part it out on ebay..

Larry

 

[AGENT 37]

Re: Four Stroke Gaskets

It doesn't look like yamaha parts are being bought up all that much though. I think that it would be a lot less effort to just unload the whole thing though. It really sucks that so many of the parts I've put on it are new.

 

[mokaction]

Re: Four Stroke Gaskets

You know I would have done a compression test on the lower oil slump, by making a rubber gasket and ataching a hose. then spray all the gasket areas with soapy water.

Also do a leak down test like rodbolt said to see if the heads are leaking. When I had the heads done I had them also re-surfaced.

I would not give up just take your time.

Larry

 

[sdsaw]

Re: Four Stroke Gaskets

The next time you have the powerhead off, Check for flatness of the powerhead base plate.
I went through a similar situation with water getting into my oil when I rebuilt my 9.8 Yam. Took it apart three times before noticing that my brand new base plate wasn't flat. I bolted the oil tank to it and milled a minimum amount to get it flat.
Been good since then.
I feel your pain and frustration with dealing with such a big job.
Good luck and I hope you figure it out.
Note: Do not try to reuse the base gasket. It didn't work for me.

Scott

 

[AGENT 37]

Re: Four Stroke Gaskets

The base plate and power head are the same original parts and I didn't have any work done to them. I can't tell if there's warp to the surface when I checked, it looks perfectly flat.
I don't think that I want to put any more money in to it. It's expensive enough just to replace those gaskets when I take the thing apart. I've gone through 3 sets of gaskets already. And I'd have to get a replacement for the crapped out tilt/trim assembly...... that should only be about five bucks right?....... It's probably less effort to convince my wife that a new motor is the way to go and write the checks to pay it off. If this motor was a horse and I a cowboy, there'd be a shot horse. No bout a doubt it.

 

[mokaction]

Re: Four Stroke Gaskets

Man, I really feel for you. so are you going to part it out or sell it as a whole???

Larry

 

[clanton]

Re: Four Stroke Gaskets

There is a service bulletin and kit, to stop the oil leaking on some of these engine, check with dealer.

 

[mokaction]

Re: Four Stroke Gaskets

would you have a copy of the buliton?? I would love to read it.. thx,

Larry

 

[AGENT 37]

Re: Four Stroke Gaskets

This would be helpful. Our local shop doesn't have it.

 

[AGENT 37]

Re: Four Stroke Gaskets

I don't know; I might sell it complete or sell the parts that are left after I do an explosives test and drag it on a chain behind the truck for about twelve miles.

 

[AGENT 37]

Re: Four Stroke Gaskets

Clanton,

Do you know what that kit consisted of?

 

[mokaction]

Re: Four Stroke Gaskets

Call Yamaha they are really good with sending info. you can find there number at http://www.yamaha.com

Also had the same thing wrong with my f200. I took some gasket sealent and a new metal gasket, and sealed with with gasket sealent (NOT the silicon s@#t). Have no problem with leaking anymore from my power head to mid section anymore.

good luck..

Larry