1985 mercury 9.8 weird water pumping issue

[green4themoney]

Hey guys i had one more issue with my brown band at low idle..... just changed the whole water pump (seals and housing) seeing as the people i bought it off had the .456 impeller on it and it has the .438 driveshaft.... anyways pumps water fine at all intervals of operation except at low idle.... pee stream becomes intermittent than just vanishes..... one thing i noticed at low idle is the exhaust is coming out of the prop...... i think there is supposed to be a relief port somewhere but i dont know if that has anything to do with it.... anybody have any input would be great.

 

[Scott Danforth]

exhaust comes out the two ports in the back and out the prop. which ever has less back pressure.

did you change the rubber bushings the water tube is inserted into?

did you change the whole pump assembly, or just the impeller?

 

[racerone]

There is a plastic washer at the top of the water tube.----It may have melted when motor overheated.-----Powerhead must be removed to inspect that item.----At the same time you could inspect idle relief for blockage.

 

[green4themoney]

exhaust comes out the two ports in the back and out the prop. which ever has less back pressure.

did you change the rubber bushings the water tube is inserted into?

did you change the whole pump assembly, or just the impeller?

yes ive changed the pump cover and water tube seal, and the lower pump assembly for the .438 driveshaft and right now i have the motor apart for another issue but the upper seal is fine and all the passages in the outboard are clear im.kind of baffled lol.

 

[green4themoney]

There is a plastic washer at the top of the water tube.----It may have melted when motor overheated.-----Powerhead must be removed to inspect that item.----At the same time you could inspect idle relief for blockage.

Upper grommet and seal are fine, and i did a test when i had exhaust cover off.... put a hose on the water tube and sent water up the tubes and there was no leaking at the upper seals it came right out the base passage where it should have.... where does the idle relief port open up in the driveshaft housing?