Buy a used 1997 9.9 hp with 110psi Compression???

[brettdawnj]

I just got done looking at a 1997 9.9 Honda 4 Stroke Long Shaft Outboard Motor. It really looked great with virtually no signs of visual wear or damage except for the paint flaking off the cowling.

Started great, sounded great, but the tell tail water pee stream was not working... no water coming out. Made me concerned and didn't run it too long. I could feel the engine getting warm to hot so I shut it down.

Took the plugs out and did a compression test on the cylinders. Both read about 110 psi (spinning it over with the electric starter so the revolutions were quit high). Manual states the spec is 156 +/- 14 (or from 142 to 170) if I remember correctly. With this level of compression drop, is this a major concern? Or will this engine still have a good service life and performance at this level? How low can the pressures go and still have a decent engine?

The owner stated when he started it yesterday, the pee stream was working. He is going to install a new water pump impeller to see if this corrects the issue.

The owner wants $700 for the outboard. Does this sound reasonable? Or should I just walk away from this one?

Thanks,

Brett

 

[hondadude]

Re: Buy a used 9.9 with 110psi Compression???

You are correct on what the compression should be...

Did you have the engine at full throttle, when you took compression? That will make a big difference.

If could be that the pee tube just got plugged with debris.

You said that the engine ran good. Was it in the water on a boat? If it was started just on a hose, that will give you limited information.

If you put it on your boat and try it, that will be the true test.

I would be apprehensive if the compression is really only 110. If could be that the valve clearances are out of adjustment. Or there could be other things more serious going on with the cylinders. You really do not know. They generally do not read the same when that happens.

As for the $700. A lot depends on what the true compression is and if the seller is still going to change the impeller. Nadaguides.com says the high retail value is about $500. (This is just a guide) Somewhere in between would not be a bad deal if everything else is good.

We generally sell these, after we get them on trade and go through them with new water pump, lower unit seal check (or reseal if needed), carb job etc. for about $750 depending on their physical shape.

That is only my opinion...everyone has one.

Maybe others with have additional thoughts.

Good luck!

Mike