1988 Johnson 150 - black ooze

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winfieldh

Seaman
Joined
Jun 24, 2004
Messages
72
Hello,

After a couple of months of sitting, I've noticed some black ooze coming out from the top portion of the lower leg. I tried removing the 4 bolts that attach the cowling to investigate further, but that didn't seem to loosen anything up (?). Could someone tell what this may be from, is further investigation needed or might this be exhaust residue working its way out? The engine had not run in several years, I went through several steps suggested here on this site. I ran 80 gallons through it last summer prior to putting up for winter and it ran like a top. I haven't fired it up this year yet....

https://picasaweb.google.com/lh/photo/Z5RnsIeeZodXLDfcL8BivTPMFGspHqGFO_myBYDLSys?feat=directlink

As always, thanks for the input.

Winfield
 
E

emdsapmgr

Supreme Mariner
Joined
Dec 9, 2005
Messages
11,551
Re: 1988 Johnson 150 - black ooze

You probably have a failing exhaust seal at the top of the lower unit. It's also often misaligned when the lower unit is dropped for a new water pump impeller, causing deformation and an eventual leak. That rubber o-ring type seal keeps the exhaust directed down into the lower unit and out the prop. Two things will occur with this failure. 1. It's just plain messy. 2. The hot exhaust gas can bleed over into the inside of the bottom of the midsection. This hot gas can/will affect the plastic impeller housing, causing it to fail earlier than normal. 320961 is the seal part. Not hard to change once the lower is slightly dropped. In addition to the 4 bolts that are visible, you will find another 2 bolts just above the prop. One of them hides under the trim tab-which must be removed.
 
W

winfieldh

Seaman
Joined
Jun 24, 2004
Messages
72
Re: 1988 Johnson 150 - black ooze

Ah, I had a mechanic change the water pump last fall prior to my running it. I doubt he replaced the seal at that time, but it would not have that many hours on it (80 gallons worth). Would that be something they might/should warranty?


Thanks, W
 
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emdsapmgr

Supreme Mariner
Joined
Dec 9, 2005
Messages
11,551
Re: 1988 Johnson 150 - black ooze

If you didn't have any issues with the black ooze before your impeller was changed, you might take it back to him. Once those exhaust seals heat up with use, they tend to expand slightly and sometimes can be difficult to get perfectly realigned when the lower unit is removed and reinstalled. A new seal should be the exact size and should slip in position perfectly-rectifying the problem.
 
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winfieldh

Seaman
Joined
Jun 24, 2004
Messages
72
Re: 1988 Johnson 150 - black ooze

Hi,
I have finally removed the lower unit and the exhaust gasket seems to be fine. The exhaust tube has the blackooze and is slimy/wet. There seems to be a gasket about half way up that is torn, but I can't reach it.

I'm afraid I am going to have to pull the PH and look at things from the top down. Not sure, but this may turn into a PH replacement project. Compression on left back was 90,90,90 right back was 90,115,105. The right head is a different head from factory so I'm unsure of what happened in the past but something got that head replaced......

What are choices for rebuilt powerheads of this type? What kind of gotchas to look out for? I assume I have to remove/reuse everything on the motor that isn't part of the head (starter, vro, flywheel, electrics, fuel pump, carbs, etc) so that will all have to come off. Anyone have experience with rebuilt heads they would like to share? Any opinions on rebuilt ph's vs a plain used motor (not rebuilt)? I have seen some on ebay and other places in the 3000 range which is also what I have seen rebuilt phs for???

Thanks,
Winfield
 
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emdsapmgr

Supreme Mariner
Joined
Dec 9, 2005
Messages
11,551
Re: 1988 Johnson 150 - black ooze

Heads usually get replaced when they warp (overheat) or when one of the ringsets lets go and the ring pcs get pounded between the top of the piston and the head. The compression of 90 lbs seems about right. Not sure where the 115 figure came from, but it is possible that the powerhead has had some work done on it. If the head that was replaced is an older, high compression head, the readings should be around 110-115. In that case, the 90 is somewhat low-close to the condemning limit of 10% variance. You can rebuild that powerhead and overbore just those cylinders which have scratches on the cylinders, or have too much wear. (ovalness or taper top-to-bottom.) If you are handy, you can do the reassembly yourself and save some $.
 
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emdsapmgr

Supreme Mariner
Joined
Dec 9, 2005
Messages
11,551
Re: 1988 Johnson 150 - black ooze

Most oversize pistons have the oversize stamped on the top, where it is visible when you pull the head off. ie: .030
 
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