Bobcat Monroe 600 won't stay running

[RanMan86]

I'm a new owner of a old Monroe 600. Worked great for a few weeks, but started to die when under load. Has gotten worse in past week of daily use - does not want to do anything more than idle after warmed up. When troubleshooting, I discovered that it was never making full power (pushing governor manually).

It will work fine for the first 15-20 minutes (about 75% power) where I can at least get the bucket into a pile of dirt. After a short time, then the engine will die while trying to go into the same dirt pile, then eventually will die by simply driving. Seems to stay running if I quickly pull it back to idle - can drive but not steer without killing engine. Once it gets to this point, it will not go full throttle without choking out.

I have checked the air filter - dirty but still looks like it has good air flow. Fuel filter is clear by blowing through it. I'm stumped as if was a fuel or air problem, the issue would be persistent when initially started. Choke works properly. Seems like something happens when it warms up.

Any help is greatly appreciated!

 

[Jerry01314]

Sounds like fuel as it gets lean mix. Add a tube to fuel filter and have someone turn key best if after fails. Pumps good, then maybe needs fresh fuel or cleaner. If pumps little then read my other notes on this.

 

[foton]

it could be electronic but try running with a partial choke and see if it runs better, if so it is running lean. If it starts running better with partial choke , it could be fuel pump , it could be a vacuum leak on intake manifold or a partially plugged fuel filter or a float out of adjustment. have fun

 

[DirtRodeo]

Hi,
On my sailboat I had a similar problem. Yanmar 37 hp. Weirdly intermittent. Turned out he fuel pickup had a 90* elbow at the top. Over the years, a perfectly round, 1/4" ball of tank debris had formed in the tube acting as a check valve. This fall, my 743 pulled a similar stunt. The priming bulb had enough sediment to block the line at certain machine angles. Hope this helps!