# Cub 1550 fuel pump probelm?



## gman51 (Mar 22, 2016)

I have a 2005 model 1550 riding lawn tractor and after mowing for maybe 15 minutes the engine acts like it is starving for gas and it quits running. The engine has 234 hours on the clock and it doesn't burn or smoke oil. It has very good compression. 
I just R&R the carb and cleaned it because the engine was surging and that cured that problem, but now I have this dying problem. It seems once it gets hot it starts to have the problem. Once it does it then it will keep doing it till I let it sit till another day. Then again it will mow for about 10-15 minutes and start quitting again.
I checked the fuel cut off solenoid and it is working. I thought maybe it was failing to hold the metering pin open after a while so I took the pin and spring out and put the solenoid back on the tractor. It was mowing ok and about time I figured that was the problem the dang thing started dying again. So that ruled out that being the problem.
I checked the fuel pump hose from the head and it has fair amount of pressure coming out of the hose. When I start and run the engine and pull off the pressure hose then the engine quits running pretty much like the engine does when it has the dying problem. So I am guessing the pressure supply pump is breaking down starving the engine for gas. I am thinking about running a hose from a container held above the engine straight to the carb and see if it still has the quit problem.
Any suggestions how to check the supply pump? I did pull the hose off the carb and cranked the engine and it is putting gas out the hose but it is not squirting out. 
The dang supply pumps are not cheap and I thought about installing an electric inline fuel ump instead. What ya'll think I should check or do with it?


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## sixbales (May 18, 2011)

Howdy gman,

Welcome to the forum.

We often get fooled when an engine shuts down, trying to figure out the problem. 

First and simplest thing to check is if it has spark. Carry a new spark plug in your pocket and when it quits, immediately pull a plug wire, put your spare plug on it, touch it to a good ground and have someone crank it while you observe for spark across the plug gap. Try to do this in a shaded area so you can see the spark. Sometimes hard to see in broad daylight. It has to be a blue-white spark. An orange-yellowish spark is not good enough.

If the spark is ok, pull the inlet hose (from the fuel tank) at the fuel pump. You should have a continuous rush flow of gas from the tank. A trickle flow is not good enough. Might be an obstruction in the system.

Is there a filter (maybe suction screen) in this system? Maybe inside the tank? Take a look. There may be dirt/debris plugging the outlet of the tank?

The fuel pump output is very low pressure, but the output volume should be ample with no back pressure.

Check it out and post back if you are still having problems.


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## gman51 (Mar 22, 2016)

Tomball eh.........I live in Waller. That's called neighbors in Texas. LOL
It's not spark it's a gas problem. I have an inline shut off valve and an inline filter but the gas flow seems to be good coming out of them. I will double check though. I think I need run gas directly to the carb from another tank to see if it still quits. If it doesn't then that should point to the pump. If I wait just a minute or less I can start the engine again but it will soon quit again. It has to be starving for gas. It is especially brought on under load when it needs more gas to run.
Update: I removed the inline fuel filter and I could blow through it easily so it isn't clogged up. I opened the inline shut off valve and there was very little gas coming through. I removed the inline valve and same thing very little gas flowing. I tried blowing back into the gas line and I really couldn't. I squeezed the gas line and I didn't feel any hard spots like it was plugged up. So now I deduce that there is a blockage in the tank. I am going to try and pressure blow back into the line tomorrow and see if under pressure it might clear the obstruction.
Is there a filter in the tank? How do I get to the tank? Remove the tractor body?


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## gman51 (Mar 22, 2016)

I pressure blew back into the fuel line to the tank and it blew whatever was obstructing the flow out because the gas in tank was bubbling now.
I also found the fuel line running along the frame had two slits in the hose and were leaking. This no doubt was why the pump could not pull gas up to the carb. It was sucking air from the holes in the line so it couldn't pull gas from the tank. I replaced all of the fuel line and the filter. When I cranked the engine the pump sucked the gas filling the fuel filter now.
I believe this will fix my starving for gas problem. I am keeping my fingers crossed.


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## rcbe (Aug 26, 2015)

if still trouble, one other thing to chk: plugged vent in fuel tank cap...


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## gman51 (Mar 22, 2016)

Problem solved. I mowed in tall grass and the engine kept right on running. I sure am glad it wasn't the fuel pump because they are expensive.
So my $300 Cub is running about like a new one now.


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