Fuel issues on yth 2548

[Bakehook]

This is a new to me mower that ran and cut great the first several times I used it. The last several times it starves for gas and requires choking to get back to the shop. I have done most of the obvious things.......
New fuel filter, checked tank venting, cleaned lines, and cleaned air filter. Ran w/ gas cap loose and also with no air filter and no change.
If I blow air back into tank until it just hisses out through cap vent then quickly reattach filter then the mower starts and runs fine......generally long enough to cut entire lawn. The pressure in tank primes the pump believe.

I am going to replace fuel pump but is the a better candidate for cause of problem? Is there anything else that would cause pump to lose its prime and run the filter dry? Pretty sure tank and lines are fine.

I had posted on small engine repair but no suggestions.

Yth 2548
Kohler cv730

 

[mullins87]

Could be a weak fuel pump. Does this engine have the vacuum operated or mechanical fuel pump?

 

[Bakehook]

Vacuum. My plan is to replace pump, and fuel lines. It acts like pump is loosing its prime but most of the time it will cut a while before it does. Filter is always empty when it cuts out.

Doesn't sound much like a spark issue to me but I am going to change plugs.....never a bad idea.

 

[DaveTN]

Before you buy a new fuel pump, why don't you do a 'Jug Test' on it. Take a fuel tank from another mower, elevate it above the carburetor and hook the fuel line to the carburetor and see if it will run. Also put a container under the fuel pump outlet to see if it is pumping gas. Do so in a ventilated area so as not to ignite fumes~~~ If it runs good, then you know it's not getting enough fuel to or through the pump. That way you could see how much fuel the pump is actually putting out while running. Still could be some small obstruction causing fuel starvation from tank to fuel pump or even going into the carburetor. I've seen small bits of trash block the needle and seat with it being above the needle. Bowl looks great, needle works and fuel may flow, but when you vibrate things the trash will get stirred up and block the inlet. Have you taken the fuel pump apart to see if it's clean and diaphragm is ok?

 

[Bakehook]

I gave thought to a pick up blockage but when I pulled the Line off on the downstream side of fuel filter I got good flow when it was lowered below tank. Also siphoned all gas from tank and inspected for debris. Clean and water free. Put in fresh gas.

I am thinking either fuel pump or bad line pulling in air and loosing prime. The pump works great when it is getting gas ( at least mower runs great until filter goes dry). If I test pump when there is no gas in filter I would expect it to not pump. When gas in filter mower runs great so I would think pump would check out fine. Intermittent problems are always the most difficult.

I can get a kohler eom pump for under $ 20 and gas line around $10. My time has some limited value (retired) and would be happy to spring for pump and line if it only rules them out as a cause.

Suggestions welcome....flying blind.

 

[Bakehook]

Solved......I think.
Tried to systematicly rule stuff out; fuel filter, gas tank vent, plugs,stale gas, etc. a pump needed to pull fuel so I got a new pump but pulled the deck and cleaned the tank first. Gas line pretty funky so that was replace and so far runs fine. Looked like the origional line collapsed enought to restrict but not stop gas flow.