MF - 135 Diesel Misfiring losing power when hot.

I"ve searched all related topics and couldn"t find symilar problems to mine. My MF135 Diesel is an ancient, oil and mug covered machine, with no lights, guages or trimmings but a true workhorse! It"s starter solenoid activates by the 3rd time you push the button and only the left brake works. BUT... it ALWAYS starts like clock work and runs like a swiss watch, come rain, frost or sunshine.

Recently she started to misfire and lose power when hot and only when hot. If pulling a big load like a road scraper she"ll start misfiring, lose power and obviously slow down, BUT.. just before she dies the 3rd cylinder kicks back in, gain power accelerate and repeat the symptom.

I had a theory obout a broken valve spring as the problematic valve gets chance to close at low rpm"s but leaks at high rpm"s. This could have been made worse with temperature. But I"ve opened the top cover and all looks fine. Neither the valves nor the pushrods are sticky.

I realy don"t have the finances to do an overhaul nor do I think its neccesary as she was fine till recently. Furthermore I can"t afford downtime as I need to start on the fire roads for the winter.

Any help will be much appreciated.

Thanks for this forum guys!

Rod

Simple things like filters or a partly blocked fuel outlet from the tank. Could be an injector is in need of attention. Could be a blocked spill return on one injector.

Must be fairly simple fault, like a partially closed tank valve or above or it would not recover like you say.

Regards, RAB