Johnson 1990 4hp impeller

[crobar]

Hello - I have a 1990 johnson 4hp deluxe model J4RDHLESR and mine is not producing any spray from the 4 weep holes mentioned in a similar thread. There is forced air coming out of these holes but no water. Is this a water cooled motor and if so what is the next step in narrowing this problem down to the cause?
Thanks - Jay

Thanks Rick for your reply. I appreciate the details and your suggestions. Now I can move ahead. I will follow up with details when I get in there and see how everything looks.
Jay

 

[Vic.S]

Re: Johnson 1990 4hp impeller

It is water cooled but AFAIK there is no telltale.

You would normally expect to see at least a few drops of water or a fine mist or spray coming out of the holes you mention with exhaust gas (not air!). Most of the water leaves with the exhaust gas under water.

If it is overheating, (cannot keep a couple of fingers on the cylinder head for more than a few seconds) suspect it needs a new pump impeller.

SEE DIAGRAM

While the gear case is off make sure you can get a flow of water up the water tube and through the engine from a garden hose.

 

[crobar]

Re: Johnson 1990 4hp impeller

Thanks Vic - Would you expect to get some misting or spray when in idle or does the spray only occur when the engine is running at a higher speed?

 

[Rick.]

Re: Johnson 1990 4hp impeller

You should see a mist at idle for sure. Rick.

 

[crobar]

Re: Johnson 1990 4hp impeller

The impeller was in fact the problem. I expected to see the edges of the impeller damaged in some way but they appeared normal. Apparently the fins just loose their stiffness with time or use and are loose their ability to push water.
Thanks to everyone for your help.

 

[tashasdaddy]

Re: Johnson 1990 4hp impeller

exactly, that is called taking a "set" it looks good, but does not flex as the drive shaft is off center in the impeller housing.