Yamaha F8 Creamy colored oil

ET · 07-05-2009, 08:46 PM

Checked my oil (8hp Yamaha 4-stroke) before the weekend and it didn't look good. Did a couple quick changes to make sure everything was clean for the fishing trip.

Came home tonight and just checked the oil again and it is creamy colored and a little high.

Obviously a head gasket, right?

I'll check compression tomorrow, but could it be anything else? The motor ran great all weekend....probably 10 plus hours of trolling.

Lead Bouncer · 07-05-2009, 09:13 PM

dont know where, but its water. Do a compression check. Watch for bleed down.

baitsauce · 07-05-2009, 09:42 PM

This is a very common problem. There have been about a dozen threads on this. You have a stuck thermostadt. Change it and you'll be fine.

ET · 07-05-2009, 11:44 PM

Quote:

Originally Posted by baitsauce

This is a very common problem. There have been about a dozen threads on this. You have a stuck thermostadt. Change it and you'll be fine.

Thank You! Hopefully that is it. I'll let you know tomorrow.

ET · 07-06-2009, 11:39 AM

I don't think it is the head gasket or the thermostat.

Compression is good. Plugs are clean. Pulled thermostat and it looks good (it isn't stuck open) though i will replace. If the thermostat was stuck open, wouldn't the engine run cold? It has been running perfectly even in 49F salt water.

Following the water trail, I pulled off the manifold and close inspection of the manifold gasket reveals that water seems to be seeping from the water passage into one of the ports.

I think that is the culprit. I'm off to buy some parts!

ET · 07-06-2009, 01:43 PM

You can see where my leak is. The top port is nice and clean while on the bottom port you can see where the water is getting by.

Gotta love the salt! I do my best to flush, but you can clearly see there are areas that just don't flush out well.

baitsauce · 07-06-2009, 03:09 PM

Glad you found it and it doesnt look to aweful hard to fix.

Keep us posted!!

//

ET · 07-21-2009, 09:48 PM

After a long weekend of trolling, I'm happy to report the gasket replacement seems to have fixed the problem. Oil is clean and fresh!

If I had not noticed the leaking gasket, it is very likely the engine would have suffered a catastrophic failure. I haven't heard of this problem with the Yamaha F8 before, but it is certainly something to keep in mind.

Is everyone checking their oil regularly?

steelheadsteve · 07-22-2009, 09:02 AM

Quote:

Originally Posted by ET

After a long weekend of trolling, I'm happy to report the gasket replacement seems to have fixed the problem. Oil is clean and fresh!

If I had not noticed the leaking gasket, it is very likely the engine would have suffered a catastrophic failure. I haven't heard of this problem with the Yamaha F8 before, but it is certainly something to keep in mind.

Is everyone checking their oil regularly?

I have a 2002 F25 that recently injested so much water in the crank case that it was way overful. Turned out that a stuck open thernostat was the problem. Who da thunk it?

garyk · 07-22-2009, 10:43 AM

Quote:

Originally Posted by ET

You can see where my leak is. The top port is nice and clean while on the bottom port you can see where the water is getting by.

Gotta love the salt! I do my best to flush, but you can clearly see there are areas that just don't flush out well.

Wow! Thanks for taking the time to post this problem & solution and that pic. Thanks!