I have a BZ482 with about 300 hours of use. Three days ago I was two hours into a 2,200 r.p.m motor against a gentle wind with my 27 ft. sailboat when the revs dropped to about 1000 and it would not go any higher. I ran it for about 10 minutes then turned it off and sailed back near my marina then restarted it and motored for 20 minutes at 1000 rpm max, back into my slip. Yesterday I changed both my fuel filters, a Racor 12 micron with sediment trap and the cartridge filter on the engine. Bleed the air out and it took an extended effort to get it to run....just didn't want to run.. But it did finally with full throttle would slowly rev up to 2000. Let it run for 20 minutes to clear out all the air. Sounded normal but responded slowly to increased throttle and would barely idle and die if put into gear. OK , let it cool down for and hour, had a snack, had a little lie-down, decided to try the other simple thing and took off the air cleaner cause it still had the original filter. Started up and immediately ran away, up to 3,200 rpm. The stop solenoid did not work so I turned off the fuel at the tank, put vise grip pliers on the fuel line near the engine then grabbed a small square of plywood and put it over the air intake, that killed it. - all in about a minute and a half. It did run smoothly I will say.. What should I look at next?
I suspect that this is caused by corrosion within the engine. There is a small spec of rust on the rack that controls the injection pump which has caused it to stick in one position.
This corrosion is usually caused by the oil not being changed often enough or the engine not being used for long periods of time and, as the seasons change, condensation forms on the surfaces inside the engine. The fix is to remove the injection pump and have it serviced at a fuel injection shop.
Turned out when I took the injection pump out both compression springs had broken and in one the pieces screwed themselves together so short, the control sleeve could drop down and jam the control rod full open. Nothing went "SPROING!' so far. YouTube videos helped a lot. This engine is used in mowers and over the road trailer refrigeration. My 2006 BZ482 has a Zexel pump 104205-2051.
