5hp Mercury Wont Pee at Idle

[jspansel]

1994 year. So the motor ran great last couple years. Started it up in a barrel this year and no water stream. Figured it was due for an impeller anyways. Impeller broke apart, I retrieved all pieces. (just the one fin broke).

Put new impeller and gaskets on. Pees super strong at anything other than an idle. Much stronger than I remember. But nothing at an idle... seems very strange to me. I give it any gas and strong stream comes out.

What could be wrong??? I primarily use this motor at idle, so this is not a good thing.

 

[oldman570]

If you just replaced the impeller, and used the old cup and lower plate, there is a chance that the wear groves in those parts are not sealing as the should with the new impeller at the lower RPM. If the motor has a thermostat and is running in a barrel the stat should open up when it reaches temp JMO
Oldman570

 

[jspansel]

It is a new cup (what the impeller presses into) and new plates. No thermostat. The sealing makes sense though. Maybe it is the main housing that is not sealing..?I will take it all apart again and make sure I have everything clean for a good seal... Would it be ok to use a very light thin film of sealant/gasket permatex to make a better seal on the main housing to the plate?

 

[jspansel]

Also at idle, instead of water, I see exhaust smoke coming out of tell tale. But like I said, any gas and it pees strong. Seems not sealed properly somewhere... I'll dig back into it this weekend.

 

[jspansel]

Just an update to close this one out... I have no clue what fixed it. But it is fixed. Just took it apart yet again a little while back and it pumped strong at idle. Think it just wasnt seated right or something. All good now though.

 

[GA_Boater]

Thanks for updating in case another member has the same symptoms. :thumb: