2001 yamaha 40 hp

[17rogue70]

i replaced the impellor in a 2001 yamaha 40hp , it seems to have intermittant air in the pee stream . is this normal? could the intermitt air be do to cavitation? also it had a very soft sounding "chirp" prior to the impellor change , but no longer hear it. could it be related to the water impellor? temp didnt get over 83.9* with a hand held infrared temp gun. the water temp was 55* during the water test. when you raise the rpms you can see a stronger pee stream, that tells me the pump is doig its job correctly.

 

[99yam40]

Re: 2001 yamaha 40 hp

That is not normal, My C40 puts out a very strong constant stream even at idle.
maybe you have exhaust leak or it is sucking air due to corrosion
Did you replace the wear plate and cup also?
or just the impeller?
The kit is just a few bucks more so I always get it as it has all that is needed unless your pump housing has a problem.
Did you check it out to make sure it was OK?
A chirp is normally what you hear due to a lean sneeze.

 

[17rogue70]

Re: 2001 yamaha 40 hp

thats what i dont understand , it all checked out good . impeller only. ill check the exhaust, the rest is clean enough to eat off/out of. thanks for the reply and advise

 

[99yam40]

Re: 2001 yamaha 40 hp

When was the last time you pulled and tested or replaced the thermostat?
and did you have much corrosion in the water passages when you looking in there?

 

[17rogue70]

Re: 2001 yamaha 40 hp

Not sure about the thermo. I don't own it, it belongs to retired woman.I will be checking the thermo tonite when I get home. Thanks for your time and help. I will give results when complete. One other thing, she added an additional 8 degrees wedge shim to her trans to compensate forplowing. (To help stop plowing with a heavy load on board.) That is 8degrees negative.could.this also be causing this situation?

 

[99yam40]

Re: 2001 yamaha 40 hp

I would not think so, as long as the water pick up is in clean(no air) water then it will not affect it.