yammy fuel pressure?

[cpj]

Gentlemen,<br />I have a 1985 yammy 115 model etlk and I am curious as to what the fuel pressure should be.Right now it has 2#'s of pressure at 2000 rpm.I think that is low. My comparison is my 1964 evinrude 9.9 that has around 6-7#'s of pressure.Any answer or guess would be appreciated!

 

[douglloyd]

Re: yammy fuel pressure?

How and why are you measuring fuel pressure?

 

[cpj]

Re: yammy fuel pressure?

Bluebird,<br />with a fuel pressure gauge,and because I am trying to trouble shoot a hesitation and think it might be the fuel pump.

 

[rodbolt]

Re: yammy fuel pressure?

there is no spec for fuel pressure that I have ever seen, replace the pumps and use a fuel vacum test. I have seen weak pumps that will allow the fuel bowls to get low when idleing and either stall on acceleration or take some time to fill the bowls. a quick test is to reprime the system immediatly before acceleration to see if the hesitation goes away or not. if the pump is more than 3 years old its on borrowed time anyway. pumps are about 38 dollars and I wont run them more than 3 years at a time.

 

[cpj]

Re: yammy fuel pressure?

Rodbolt,Thank you for the reply! I picked up a fuel pump today and plan on installing it later tonight or tomorrow.Just for giggles I will compare the pressures and post the results.If three years on a pump is to long than I consider myself lucky because it has to be at least 10 years or more old!

 

[rodbolt]

Re: yammy fuel pressure?

yep<br /> and its a leading cause of power head failures on oil injected yams. the excess fuel from a ruptured diaphram will wash the oil off the cyl that it takes the pulse from.

 

[cpj]

Re: yammy fuel pressure?

the good thing about my motor though is it is now premix instead of oil injected.I just didnt trust a 20 year old oiling system. Plus the controler was shot and it kept filling the motor tank and wouldnt shut off.

 

[cpj]

Re: yammy fuel pressure?

I changed the pump and I still had around 2 pounds of pressure @2000 rpms.So I guess that 2 pounds is what they put out.I did take the old one apart and found that the nuts and bolts inside it had rusted away and there was alot of crud inside it.Glad I listend to my local shop and replaced it rather than rebuilding it.