mf135 running rough

peanut pete · Sep 12, 2020

after replacing some broken rings, honing cylinders, new bearings, replacing valves and gaskets the little 3 cylinder diesel still runs rough at around 600 to 900 rpm. Suspect the injector pump, does anyone have any suggestions of what to look for or avoid? is injector pump worth repairing or just replace with a new one? thanks in advance pete.

Dieseltech · Sep 14, 2020

If engine starts OK when hot, injection pump hydraulic head should be OK and repairing the pump should take care of it. If the head is severely worn engine won't start
when hot. Injectors might need cleaned and reset too, or tips replaced and opening pressure reset. I just finished testing a White/Perkins pump that needed a new head as
it would not start hot as rotor was severely worn.

peanut pete · Sep 14, 2020

Thanks, I have replaced the injectors. it starts and runs fine hot or cold, seems to have plenty of power at full revs. its just rough between 600 and 900 rpm.
i have not touched the timing, is it worth trying that by twisting the pump, as some have suggested?
if the hydraulic head appears ok does that mean it would be just a reseal kit? i appreciate that we wont know until it comes apart. are there any tests i can carry out while its on the engine to narrow down the problem, in order to estimate the cost vs replacement,, thanks again.

mf135 running rough

peanut pete

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Dieseltech

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peanut pete

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