The fuse that blew was on the board and should have been a 15 amp not a 20 amp that was there so should be this F6 power fuse. I'll try and find some time this weekend to test the voltage at the pump. I'm just curious if this is a fuel/electrical problem (and I think it may be) why did it not start until I tried using the mower PTO for the first time this spring?
I need to get better at this electrical stuff I've never been good at it. Thanks flymo.
The wiring diagrams are very complicated - gives me a headache every time. TM1517 does include a theory of operation page for most circuits, so that can help puzzle things out sometimes. As to why the fuse blew only with the PTO on, the PTO solenoid does take some current, so maybe that was the straw that broke the came's back? I'm hoping you don't have a more general problem, one that lead the previous owner to replace 15A fuses with 20s.
Bob, thanks for the tip on the wiring near the PS valve - I will check it.
Well I tested the fuel transfer pump in the tank and checked the inlet screen/filter which was clear. In doing the Fuel Transfer Pump Flow Test I obtained the minimum 15 oz of fuel when disconnecting the fuel inlet hose at the filter. However, I received zero fuel at the fuel return hose at the tank transfer pump. You can hear the fuel shutoff solenoid turning on when the key is turned on as well as the plunger moving.
Assuming I did the test correctly I guess I need a new transfer pump? How would I check electric power to this pump? What should I check next?
Hank, I think your test proved that the transfer pump is just fine. Per the test description, if the return hose is not delivering the correct amount, check/replace the filter and for a restricted return hose.
Fuel Pump Flow.jpg I think that's good news - your pump is delivering enough fuel, but for some reason it's not getting through the filter to the motor or the return hose. It could be something as simple as a filter needing replacement.
So I had replaced the fuel filter in March or April but took off the filter head assembly today and re-checked everything but no change. Still starts up but runs rough and slow, no throttle response, and dies out. I didn't check the whole length of the return hose but I'm not sure that's the problem seems like there is something else not right.
One other thing that may be worth mentioning is the fuel filter assembly. I believe the same day that I started having this problem I had tried to fix a very small leak that I think was coming from the fuel shutoff lever. When I originally replaced the filter I stupidly forgot to loosen the screw first and may have pushed too hard on the lever. So I had loosened the screw and tried to push the lever in as it seems a little loose and then retightened the screw. Maybe I put the little plastic piece that came out back in wrong. It is lined up and fits to the lever in the open position but maybe it only goes in one way??
Hank, unfortunately the fuel filter assembly on the 455 is notorious for having problems - the shutoff valve sticks and then the pot metal the thing is cast from just breaks off. It happened to me the first time I went to change the filter, and I had to get a whole new assembly. Now I just replace the filter without using the shutoff - very little fuel spills out, just a couple of drops.
Since you have a test which is clearly failing, the next logical step is to understand why. It seems to me that for some reason very little fuel is getting through the filter, which is consistent with your symptoms of poor running and being unable to throttle up. Again, I think that's good news - it would be worse if the injection pump was acting up.
Hank, re-reading your latest message, and reconsidering possibilities, I think it is likely that your fuel shutoff is mostly closed - that is, the lever has become separated from the actual valve. In any event, the solution is still to replace the filter assembly.
Yeah I've been reading about the problems with the filter assembly. It's worth a shot so I'll try and get a new one in this week and see if that does it. And next time I replace the filter I'll definitely do it without touching the shutoff valve. I probably should have mentioned this in the beginning, but when my troubles started with using the mower PTO for the first time I just assumed something electrical at first.
Hank, very natural to first look for an electrical problem - after all, you blew a fuse! I'm hoping that you don't have two separate issues.
I worked as a high-level troubleshooter of electromechanical systems for many years, and it was a lesson I learned the hard way - fix what clearly seems to be wrong, even if it does not account for all the symptoms.