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9020 Loses Power


Titan

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My 9020 loses power when it warms up. This problem has gradually gotten worse over the summer. When I first noticed it, I could correct the problem and gain most of the power back by giving the engine a little choke. Lately, I've sometimes had to run it on full choke, and then even that did'nt compensate for the power loss. I then began turning off the mower, stopping forward motion, and letting the tractor run at half throttle for a few minutes. I could then shut off the choke and the engine would run at full power for a short time, and then begin losing power again. I've since swapped out the carb with a known good one. After that did not correct the problem, I removed the fuel pump and replaced the diaphram. This didn't correct the problem either. It still loses power once it warms up. I'm convinced it is a fuel problem, but where do I look now? I should mention that the fuel filter is fine.
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Blow back through the pickup tube from the tank, to make sure there is nothing like a piece of cork float blocking the suction line causeing a restriction.
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Titan: Is it also running hot? I had a loss of power last year and found out it was running way too hot, due to plugged cooling fins. Stan is also right about having these engines fine tuned for good performance. Good Luck, Keep us informed, Ken
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HAVE YOU CHECKED THE COMPRESSION WHEN THE ENGINE IS HOT.WHEN COLD, ENGINE START ALRIGHT,BUT AS IT WARMS UP THE VALVES EXPAND WITH LOSS OF COMPRESSION. THREFORE LOSS OF POWER.
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My 720 loses power when the point gap gets too narrow. Set them at a strong .019, and make sure that they are clean. These engines have a tendency to get some oil vapor through the points plunger. Every couple of months I open the points box and spray a little brake cleaner on the points, then blow them off with compressed air. Hope this helps! Dave
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Are you positively sure the fuel pump is good? You need around 5 PSI. Have you checked the pressure? A low pressure electric one from NAPA is a cheap remidy most of us have went too. When is the last time you cleaned/inspected the crankcase breather and tube? As mentioned above, are points plugs 100%. Is oil squirting out of the crankcase, up into the point box and soaking the points? How old are your ignition wires? And, don't forget to use some Seafoam gas additive.
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If you have an old ignition coil it can lose dielectric strength when the coil gets hot. Could check the resistance between primary and secondary with an ohmeter when the coil is cold and again when it is hot. Also make sure your breather is clean. Paul
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When you say looses power what does that mean?It surges?It hunts with the governor?It misfires?Backfires?Cuts off clean?RPM continually drops?
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It loses RPM's and power. Initially, I could somewhat correct the problem by giving it a little choke. I then started having to give it more check to bring the RPM's back. Then, even that wouldn't correct the loss of power. Actually, the last couple of times I've used the tractor since working on the fuel pump, there hasn't been a significant problem. If the problem returns, I'll have to check some of the suggestions which have been offered. Thanks for the replies.
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  • 3 weeks later...
Titan, Check the fuel tank outlet for a partial blockage. Had this same problem with my Farmall 460 recently. It would start and run fine for about a half hour and then it would act like it was running out of gas..die out and surge...die out and surge. The sediment bowl looked fine so I drained the gas (ran real slow), and took the bowl off the tank. The inlet to the bowl was plugged with rust chips. I cleaned it out and it runs fine now. I can see a tank cleaning will be needed sometime in the near future.
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