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81 Johnson 9.9 with a drinking problem

R

ripperace

Contributing Member
I've got one in the shop that I've got trouble figuring out. It's a rebuilt 81 9.9 that has 30 over pistons, the 15 exhaust, and HAD Boyesen reeds in it. The guy brings it to me because he'd just had the work done to it this past spring. When he was running it, the thing suddenly lost RPM, then it wouldn't idle, and became hard to start. He told me that since he's gotten it back that every time he ran it, the prop had white slimy oil in the exhaust hub. Like when you fire it up the first time in the spring, or if you run engine tuner through it. So I put it in the tank, had a heck of a time starting it and keeping it running without running it over half throttle. So I go through the normal checks, plugs, compression, spark, fuel system. When I pulled the plugs, the bottom plug was getting obvious water contamination as there was the same white slime all over the insulator that the guy was seeing in the prop hub. So I started by pulling the head and exhaust covers to see if maybe a gasket had failed. Nothing, they were sealing excellent. I pull the powerhead to check the mating surfaces on the exhaust tube and water tube grommet, both of which were sealing good. Now I start looking for cracks. I can't find any evidence of any cracking anywhere. The only thing I found wrong with the powerhead was the reeds. The bottom reed stop had been hit with the connecting rod, bending the screws, and the reed was pretty much destroyed without breaking completely apart. Since this is the only thing I found wrong with the powerhead, does anyone think the broken reed has anything to do with this powerhead taking a big drink on the bottom cylinder? I'm seriously stumped on this one guys. Nothing, and I mean nothing else was wrong that I seen. Any ideas?
 
Rod bearings and wrist pin bearings were replaced. I checked the exhaust tubes gasket surface with a straight edge, and it's perfectly flat along with the mating surface on the block. The water tube grommet and gasket for that tube was replaced by me. The only thing, like I mentioned before, that is even remotely wrong with this thing by obvious damage was the reed stop and reed that was damaged. When I took a straight edge across the reed stops, it appears that someone kicked them open as they weren't equidistant from the tips of the stops to the face of the reedplate. Will a broken reed make one suck water though? I've never seen a 9.9 have the issue this one is having, and I'll be damned if I can find anything wrong with it other than that broken reed and damaged reed stop.
 
It's got all the 15 parts. I guess I should have elaborated more. If it would have been me, I would have shimmed the reed stops rather than bending them open, but I digress. I'm more than likely going to throw new reeds and stops in this thing and see if this was the cause of this thing taking on water first. I just never had one drinkin water when a reed was messed up. Pukin gas back at me? Yeah, but not drinkin water.
 
ripperace said:
It's got all the 15 parts. I guess I should have elaborated more. If it would have been me, I would have shimmed the reed stops rather than bending them open, but I digress. I'm more than likely going to throw new reeds and stops in this thing and see if this was the cause of this thing taking on water first. I just never had one drinkin water when a reed was messed up. Pukin gas back at me? Yeah, but not drinkin water.
Click to expand...

Any gasket that keeps water out and reed block if deformed.

Rocket science these are not aye.

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