Question for the pro's -

[sschefer]

I'm really puzzled by this and need some thoughts to try and bring some sense to it.

What would you think if you opened up a 1991 engine and found all 4 cylinders clean as a whistle and the cylinder sleeves still had the honing marks in them. Compression was 135-137.

The reeds are shot and the exhaust baffle, Exhast plate and intake gaskets show signs of leaking. I found exhaust carbon in the water passages on the baffle side and at the exhaust plate.

There were only trace amounts of carbon on the pistons and cylinder domes with #1 haveing more than the rest.

I would suspect a recent powerhead change but the thermostat and poppet cover bolts had a lot of corrosion on them that indicated they had not been removed for a while.

I suspect that back in 91, during breakin, it sneezed really bad and it's never run right since.

Any ideas? I'm questioning whether I should continue with the rebuild or consider it a lemon and junk it.

 

[Chris1956]

Re: Question for the pro's -

Gee, Maybe it was run sparingly and kept in salt water. Are the exhaust baffle and cover serviceable?

How are the reed valves shot?

Since it has pristeen pistons and cylinders, I would think a rebuild is in order. You could toss on some used reeds, some exhaust gaskets and carb kits and run it.

 

[sschefer]

Re: Question for the pro's -

Gee, Maybe it was run sparingly and kept in salt water. Are the exhaust baffle and cover serviceable?

How are the reed valves shot?

Since it has pristeen pistons and cylinders, I would think a rebuild is in order. You could toss on some used reeds, some exhaust gaskets and carb kits and run it.

Chris, the reeds were shot, just about every petal was a cricket. The baffle plate was leaking around several of the bolts as was evidence by rusty bolt shanks. Bores are round and within spec's, taper is .0015. Rod and main journals are clean, bearings are all good. I ran a fine hone down the cylinders and put the pistons back in with standard rings. Skirt clearance is equal and good throughout the stroke so the rods are straight.

The only thing I can figure is that the original problem was a big sneeze during break in. Probably a new owner that didn't understand how the choke worked. That probably blew the baffle gaskets and caused the intial problem. I think (just guessing) that no one suspected that to be the problem so they went after everything else. I just discovered that the lower exhaust tube gasket was missing so somebody was hunting for the problem before me. The clean cylinders was definitely done by steam and not SeaFoam. SeaFoam is good but not that good!

Having seen and inspected every single part of this engine I think the motor is a freshy with very low hours. If you put my purchase date (Oct 08) together with the economy and all the boat shops closing, I think I've got an engine that was sitting in a shop's back room somewhere and sold at auction when the place went bankrupt.

The only reason I went this far with it is because I was curious and I have a backup motor if I really want to get back out on the lake.

I'm bolting it back together now. We'll see what happens in a week or so. I'm going to rebuild the lower shaft cover, mount and tilt/trim while I've go it all exposed.