1994 Force Mercury 90 hp piston ring info

venxxxxx

Seaman
Joined
Apr 25, 2011
Messages
55
Where could I get a set of rings for my rebuild. The lower ring got stuck and broke when i try to loosen it.
Engine is a 94 90hp force : Serial OE069390 OEM ring set serial: 820457A 2

Thanks
 

roscoe

Supreme Mariner
Joined
Oct 30, 2002
Messages
21,657
Re: 1994 Force Mercury 90 hp piston ring info

So you are doing a rebuild.

Did you replace the pistons, or are they the original factory pistons?

If factory original, I am not aware of a source. Perhaps Frank knows of one.

You may have to replace the piston to get the job done.
 

jerryjerry05

Supreme Mariner
Joined
May 7, 2008
Messages
17,923
Re: 1994 Force Mercury 90 hp piston ring info

This site sells piston rings.
All over the net,you can find them.
I sometimes buy here or iboats. com
Your local Mercury dealer has them too,or can get them.
Oh yea e-bay.Just be carefull when buying there.
Now always replace the rings when doing a rebuild.
What happened??
Any scoring or damage?
 

venxxxxx

Seaman
Joined
Apr 25, 2011
Messages
55
Re: 1994 Force Mercury 90 hp piston ring info

There wasn't a huge scored along the piston wall. But engine sure was overheat and the ring at the bottom cylinder get stuck pretty well. I sprayed penetrating oil (rust bolt spray) on it and let it sat over night and that didnt help. SO had to take out the flat screw driver and hit it with a hammer to break loose parts of the rings off.

I still can use the OEM piston, just need to file the groove a bit larger. And its only the bottom groove/ring. The top one has a bit of sand damage but not too much where it would be useless. Its probably just need rings replace on the last cylinder. The rings on the other two cylinders are still good. I got a low compression of 100psi from them when the engine was dried up and at neutral.

Now its lubed up and I reckon it would be over 120psi, which is good enough. I found a ring set on Ebay for $29 and it took some cross reference to get the correct set. I will only use the bottom ring and keep the top one. Everything is still OEM, down to the gaskets set which seems almost new.

This engine wasn't in use much and when it was, the previous owner didnt flush it right. He told me he sprayed water at the nozzle intake when out of the water 'like a jetski'- what a goof i thought when he said that. But anyway, hopefull I can get it back and running by this memorial day weekend to take it out for a spin.
 

jerryjerry05

Supreme Mariner
Joined
May 7, 2008
Messages
17,923
Re: 1994 Force Mercury 90 hp piston ring info

(There wasn't a huge scored along the piston wall)
Pics???
Any scoring can be dangerous.
(just need to file the groove a bit larger) ??????
That tells me the parts aren't right and your gonna be rebuilding it again???

Only one way to do it???
 

jkoppe73

Petty Officer 3rd Class
Joined
Mar 17, 2010
Messages
79
Re: 1994 Force Mercury 90 hp piston ring info

There wasn't a huge scored along the piston wall. But engine sure was overheat and the ring at the bottom cylinder get stuck pretty well. I sprayed penetrating oil (rust bolt spray) on it and let it sat over night and that didnt help. SO had to take out the flat screw driver and hit it with a hammer to break loose parts of the rings off.

I still can use the OEM piston, just need to file the groove a bit larger. And its only the bottom groove/ring. The top one has a bit of sand damage but not too much where it would be useless. Its probably just need rings replace on the last cylinder. The rings on the other two cylinders are still good. I got a low compression of 100psi from them when the engine was dried up and at neutral.

Now its lubed up and I reckon it would be over 120psi, which is good enough. I found a ring set on Ebay for $29 and it took some cross reference to get the correct set. I will only use the bottom ring and keep the top one. Everything is still OEM, down to the gaskets set which seems almost new.

This engine wasn't in use much and when it was, the previous owner didnt flush it right. He told me he sprayed water at the nozzle intake when out of the water 'like a jetski'- what a goof i thought when he said that. But anyway, hopefull I can get it back and running by this memorial day weekend to take it out for a spin.

oh, this is going to turn out just fine.
 

venxxxxx

Seaman
Joined
Apr 25, 2011
Messages
55
Re: 1994 Force Mercury 90 hp piston ring info

(There wasn't a huge scored along the piston wall)
Pics???
Any scoring can be dangerous.
(just need to file the groove a bit larger) ??????
That tells me the parts aren't right and your gonna be rebuilding it again???

Only one way to do it???

Hi Jerry, :)

Well, just the bottom cylinder, lower rings get stuck due to overheating. The score isn't much at all, its caused by the stuck ring. I dont think its such a big deal as long as the groove get back to its original space required to fit the rings. Cylinder walls are nice and smooth, no damage at all.

I could replace another piston head but haven't found a replacement. I saw some on Ebay but they're for newer 95-99 engines which dont have the two port sides-

If someone got a good '94 piston head laying around, I could use it ? ;)

All the parts are OEM standard, no modifications or boring needed.
 
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