1989 Force 85hp Compression test done and...

[bradleeson]

#1 = 115
#2 = 118
#3 = 95

So it is probably best to do the rings before taking it out right? May have trouble or poor results if not?

When I sprayed oil into #3, and tried again I got 115.

So It should just be rings I think.

Also I am looking around for the parts. looks i need to order two 2-packs. Seems the 3-pack is not longer made? Also do I just get the overhaul kit set with all the new gaskets or is there something more streamline?


Thanks as always.

 

[steelespike]

Re: 1989 Force 85hp Compression test done and...

May just be stuck rings.
Get some seafoam and do a decarb follow directions on the can.

 

[john from md]

Re: 1989 Force 85hp Compression test done and...

Do a decarb in accordance with the instructions in the sticky that is posted in the FAQ section. There's a good chance that you just have carbon build up which is causing the rings to stick. After the decarb, check the compression again. I think you will be pleasantly surprised with the results.

John

 

[Frank Acampora]

Re: 1989 Force 85hp Compression test done and...

Agree! Rings on outboards get so little running time that they almost never wear out. They only go bad when a cylinder is scored and then the compression will be well below 60 PSI.

Sounds like you may have some rings varnished into the grooves. Try the seafoam first.

 

[bradleeson]

Re: 1989 Force 85hp Compression test done and...

This is a great thing to be hearing. Stay tuned.

Thanks..

 

[bradleeson]

Re: 1989 Force 85hp Compression test done and...

Do a decarb in accordance with the instructions in the sticky that is posted in the FAQ section.
John

NEVER MIND I FOUND IT.

 

[TexasBayFisher]

Re: 1989 Force 85hp Compression test done and...

This is a great thing to be hearing. Stay tuned.

Thanks..

Did you use the powertune/seafoam, and what was the result?
Did the compression come back up in the problem cylinder?

 

[bradleeson]

Re: 1989 Force 85hp Compression test done and...

Not sure yet, was supposed to be done tomorrow, but have to drop the lower unit now because during LU lube change the shift pivot screw was removed.

Plus weather has not been on my side.

 

[cr2k]

Re: 1989 Force 85hp Compression test done and...

Ah! The number one outboard service rule. (that no one tells you) NEVER remove a phillips head screw from the lower unit. All oil screws are flat head. Most are large some vent screws are small, but ALL are flat head.

But don't be dismayed, most of learned that lesson that way too.

Good luck on the compression.

Also never remove any screw that is or was under a decal.

 

[bradleeson]

Re: 1989 Force 85hp Compression test done and...

It was actually a flat head, and when I went out there this morning I got it back in without dropping the LU. Happy about that!

 

[GrindKore]

Re: 1989 Force 85hp Compression test done and...

I have had similar problem with my Force 90 last year, read my thread here http://forums.iboats.com/showthread.php?t=266436

 

[bradleeson]

Re: 1989 Force 85hp Compression test done and...

It was actually a flat head, and when I went out there this morning I got it back in without dropping the LU. Happy about that!

I lied: see post http://forums.iboats.com/showthread.php?p=2047899#post2047899

 

[bradleeson]

Re: 1989 Force 85hp Compression test done and...

Ok, so I had the shop do a decarb on the motor, since they had a tank to do it in. I then ran about 5 gallons of gas with '"procleen" through it on the lake; and here are the numbers now.

2nd time around

#1 107
#2 119
#3 100

So do I just need to keep runner it awhile or is something going on? It started and ran great, but would miss periodically at wot and other speeds as well. When I took the cowl off I found a bolt that came out of the manifold (top right bolt) Do you suppose that could have contributed?

 

[TexasBayFisher]

Re: 1989 Force 85hp Compression test done and...

The carbs probably need rebuild kits and synchronized like mine do.
For fuel run SHELL premium gasoline, it has 5x more detergents than other gasolines and it will prevent fouling. Install new plugs also. NGK BUHX # 2522
When you order the carb kits order manifold gaskets while you're at it (but good luck finding them)

Correct carb kit part # is FK10125 (I ordered a different part # and it was wrong.) You need 3 of them.

 

[bradleeson]

Re: 1989 Force 85hp Compression test done and...

Thanks Tex....

 

[bradleeson]

Re: 1989 Force 85hp Compression test done and...

Hoping to get an opinion on these numbers?

Ok, so I had the shop do a decarb on the motor, since they had a tank to do it in. I then ran about 5 gallons of gas with '"procleen" through it on the lake; and here are the numbers now.

2nd time around

#1 107
#2 119
#3 100

So do I just need to keep runner it awhile or is something going on? It started and ran great, but would miss periodically at wot and other speeds as well. When I took the cowl off I found a bolt that came out of the manifold (top right bolt) Do you suppose that could have contributed?

 

[john from md]

Re: 1989 Force 85hp Compression test done and...

Decarbing an engine is not always a one time process. Your numbers are still low and suggest that the rings are still sticking. Here is what I suggest.


YOU do a decarb in accordance with the instructions in the FAQ, not some kid in the shop. This can be done on muffs or in the waterThe information that we have developed on this forum comes from years of experience and works well. After doing the decarb, spray DEEP CREEP into the cylinders and rotate the crank a few times whenever the boat will sit. This will also help to loosen carbon and varnish.

The bolt coming out of the manifold will allow air to enter and cause a lean condition. That will cause the engine to act like it is missing. I suggest that you get a long 7/16 and 1/2 inch wrench and check the torque of all manifold bolts and carb nuts.

Also, I see nothing about your having cleaned the carbs or replaced the fuel pump diaphram. Have you done these things?


John

 

[bradleeson]

Re: 1989 Force 85hp Compression test done and...

Ok, so I had the shop do a decarb on the motor, since they had a tank to do it in. I then ran about 5 gallons of gas with '"procleen" through it on the lake; and here are the numbers now.

2nd time around

#1 107
#2 119
#3 100

So do I just need to keep runner it awhile or is something going on? It started and ran great, but would miss periodically at wot and other speeds as well. When I took the cowl off I found a bolt that came out of the manifold (top right bolt) Do you suppose that could have contributed?

Decarbing an engine is not always a one time process. Your numbers are still low and suggest that the rings are still sticking. Here is what I suggest.


YOU do a decarb in accordance with the instructions in the FAQ, not some kid in the shop. This can be done on muffs or in the waterThe information that we have developed on this forum comes from years of experience and works well. After doing the decarb, spray DEEP CREEP into the cylinders and rotate the crank a few times whenever the boat will sit. This will also help to loosen carbon and varnish.

The bolt coming out of the manifold will allow air to enter and cause a lean condition. That will cause the engine to act like it is missing. I suggest that you get a long 7/16 and 1/2 inch wrench and check the torque of all manifold bolts and carb nuts.

Also, I see nothing about your having cleaned the carbs or replaced the fuel pump diaphram. Have you done these things?


John

I currently have the carbs off and I am rebuilding them. I have not replaced the fuel diaphram. I did do the impeller and gasket, but not the fuel diaphram while I was in there. I will go at it again one step at a time. Thanks John.

 

[john from md]

Re: 1989 Force 85hp Compression test done and...

I'm confused. You said you replaced an impeller and gasket but did not do the fuel diaphram while in there. Unless Force geometry has changed, the impeller is in the lower unit and the fuel diaprham is on the side of the power head.

John

 

[bradleeson]

Re: 1989 Force 85hp Compression test done and...

Oh good luckily I was confused. I will change her.