RMCIII 838 #1 Posted August 5, 2013 Good Evening All: I have posted this same post in JD forum since it is a JD mower, but thought, what the heck maybe someone knows a little more in here than the Green forum. The problem is simple, but is pain to figure out. It is on a F932, it happens all the time, and there is no set pattern as to why it is happening. It will not throttle up when the lever is pushed forward. If you throttle up and down eventually it will throttle up and runs fine. It has nothing to do with allowing it to warm up, it can run for an hour, idle it down, then throttle it back up again, and it will not respond. The entire carb has been removed, jets cleaned, bowl has new seals. Intake seals are fine coming from head to the carb. Linkage is nice and tight. Springs all appear to be correct size and function as they should. Here is the kicker. When you throttle it up, the gas will fill up in the bowl, but will not flow over into the intake to the heads. It would seem that maybe there is a bypass we are not aware of or????? Need help. Other than this little(pesky) issue, the F932 runs outstanding. Only 1600hrs. on the Yanmar 28hp. gas engine. Come on Horses, show the Deeres who knows more. Share this post Link to post Share on other sites
Jeff-C175 7,206 #2 Posted August 5, 2013 but will not flow over into the intake to the heads. That's not really a good description of how a carburetor works though... What happens is that the vacuum created in the engine is supposed to SUCK the fuel through the metering orifices. You should never 'see' raw fuel pouring into the engine. I think you've got a partial blockage in one of the teeny-tiny fuel orifices in the main metering circuit. Share this post Link to post Share on other sites
RMCIII 838 #3 Posted August 6, 2013 but will not flow over into the intake to the heads. That's not really a good description of how a carburetor works though... What happens is that the vacuum created in the engine is supposed to SUCK the fuel through the metering orifices. You should never 'see' raw fuel pouring into the engine. I think you've got a partial blockage in one of the teeny-tiny fuel orifices in the main metering circuit. Never said I saw raw fuel pouring into engine. As the thread reads, it says, "the gas will fill up in the bowl". Not sure of the entire flow of fuel, but dam sure, the bowl represents the carb//// Thanks Share this post Link to post Share on other sites
maxed500 10 #4 Posted August 6, 2013 not that i would be able to help, but if you recorded a video, put it here for everyone to see/hear, plainly show the carb, and get it to act up, maybe someone could diagnose the cause? Share this post Link to post Share on other sites
Jeff-C175 7,206 #5 Posted August 6, 2013 Never said I saw raw fuel pouring into engine Nope, and I never said you did either... more or less just clarifying the issue is all, cuz when you say stuff like "... flow over into the intake ..." it kinda sounds like that's what you are expecting. When you cleaned the carb, did you take notice of those little pinholes in the body of the carb near the throttle plate? Are you sure they were all open? It only takes a tiny little speck of 'crud' to partially plug them up. Share this post Link to post Share on other sites
RMCIII 838 #6 Posted August 6, 2013 Pinholes all were clean. Used tiny needle to clean each individual hole out. Will try and get a video to upload. He is in Illinois, I'm in Ohio. Share this post Link to post Share on other sites
Callen 64 #7 Posted August 6, 2013 RMC, When this same condition develops on my race engine (5HP Briggs) the first thing I check is for a closed gap on my plug then for a partially blocked idle circuit then the flywheel to coil gap then a partially sheared flywheel key. Rust or any kind of build up on the flywheel, where the ignition can rub it, won't let the coil load up till it gets up in RPM. Share this post Link to post Share on other sites
