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1990 johnson 90hp problems

S

steve

Contributing Member
" 1. This is an old 1990 john

" 1. This is an old 1990 johnson 90hp motor and there is a good bit of oil leaking/ coming out from the prop area. Is this a serious concern, or is this normal for this engine.

2. When i flush the engine there is a few spots where the lower unit/upper unit join where water shoots out in fine lines. Is this a problem or is this nothing to worry about.

Both of the above problems have been there for a while and the engine has been running fine, i really dont want to mess with these issues if there not causing damage to the motor.

Thanks for your help,
Steve "
 
" im pretty sure its unburned

" im pretty sure its unburned fuel.

If it is unburned fuel, should i be concerned?

And what about the very fine streams of water coming out between the upper/lower unit while flushing, Will this cause bigger problems?

thanks,
steve "
 
"Steve.... The water shooting

"Steve.... The water shooting out between the lower unit and the exhaust housing is nothing to be concerned about. That is due to the fact that there is no gasket used in that location, nor is it needed. When the unit is off, and a few minutes before re-installing it (to avoid that leakage problem), it is best to apply a bead of "Marprox Sealer 1000" or "Boat Armor Sealer 1000" to the upper lower unit surface. That bead will dry and act as a sealer to correct that situation.

The oil dripping problem.... Loosen the lower unit drain screw to compare the color of it with what is dripping out. If oil has been leaking from the lower unit, water would seep in, and that water would be right at that drain screw area.

If there is no water present, and the oil is a different coloring than the dripping oil, I wouldn't be concerned about the lower unit. However, top the gear lube off by filling from the bottom until it flows out the top level screw hole. If water is present, obviously that problem should be taken care of immediately.

If however, all is well with the lower unit and the dripping oil is very black in coloring, I would strongly suspect that this is simply excess fuel and oil that is being drained down through the inner portions of the soot and carbon encrusted areas of the exhaust tube, picking up the black coloring on its way down to the prop area.

Check the compression and spark.... compression 100+ psi and even on all cyls. Spark, with plugs out, should jump a 7/16" gap with a strong blue flame on all cyls.

S/Plugs should be Champion QL77JC4 plugs with a gap set to .040.

Joe
"
 
" thankyou Joe, your knowledge

" thankyou Joe, your knowledge and willingness to share info on boat engines is amazing and helpful to many. "
 
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