Last December I posted this topic here and I got a lot of good and logical tips on what could be going on with my engine. After cleaning the tank, replacing hoses, filters, lift pump, sending injection pump to a diesel shop and reinstalling the original propeller. It would still go up to 3000rpm no load and 2000rpm under load (no smoke at all). The guy at the diesel shop, who didn't want me to take him the injection pump because he said it was almost impossible that there was something wrong with it, but I insisted (and payed for it...) asked me for the service manual and found that there is an adjusting screw for the load control in the governor. This screw is right beside the water pump (raw) and is covered with a locking nut. I took the nut off tighten the screw half turn and tested the engine under load and it decreased by 200rpm so I went the other way and set it to 2800rpm under load (more that that I would se some black smoke). After an year of scratching my head the engine is finally working as a champ. Most people told me that the governor shouldn't be touched, that is factory set and you can damage the engine, but in my case it worked and as long as you don't rev the engine at more than the recomended rpm it should be fine. BTW the boat is a Catalina 30 '84 and the engine has 750 hours. I hope someone can beneffit from my experience.
Universal m25 low rpm under load (FIXED !!!)
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Govenor adjustments
All the manuals tell you not to change the govenor adjustment. This may just as well be to protect the engine from the idiots who would try to gain speed/hp by changing the adjustment. Not to mention lawsuits. As long as you do not run the engine over the max RPM, you will be fine. When I was a small boy my best friends dad had a Farmall Cub tractor. It was our transportation to places far and near. We had a custom bent piece of fence wire hanging by his gate. This precision, custom bent wire was to hold the govenor open so the tractor would run much faster.
All the manuals tell you not to change the govenor adjustment. This may just as well be to protect the engine from the idiots who would try to gain speed/hp by changing the adjustment. Not to mention lawsuits. As long as you do not run the engine over the max RPM, you will be fine. When I was a small boy my best friends dad had a Farmall Cub tractor. It was our transportation to places far and near. We had a custom bent piece of fence wire hanging by his gate. This precision, custom bent wire was to hold the govenor open so the tractor would run much faster.
Governor adjustment
We have an '84 C30 with the M25. The PO told me to turn the nut 1/4 to 1/2 turn every month in order to grease the raw water pump. After finding out that about half dozen things he said to do were bs, he either didn't know what he was talking about or was trying to show how much he "did" know. That said, when my raw water pump started leaking water into the crankcase, didn't know that was the problem then, I talked at length with a Kubota supplier thinking it was a head gasket or worse. He said that was the governor nut and the cover was supposed to be tamper proof, meaning don't mess with it, it was set at the factory and should not be changed. However, he said if it has been messed with, make adjustments just as you did, small increments and reversable.
We have an '84 C30 with the M25. The PO told me to turn the nut 1/4 to 1/2 turn every month in order to grease the raw water pump. After finding out that about half dozen things he said to do were bs, he either didn't know what he was talking about or was trying to show how much he "did" know. That said, when my raw water pump started leaking water into the crankcase, didn't know that was the problem then, I talked at length with a Kubota supplier thinking it was a head gasket or worse. He said that was the governor nut and the cover was supposed to be tamper proof, meaning don't mess with it, it was set at the factory and should not be changed. However, he said if it has been messed with, make adjustments just as you did, small increments and reversable.
Same problem
Last week when I responded below, my M25 was running great. Sunday we went out, windy, rough and I'm low on fuel. Before we could get the sails up the engine rpm started dropping and finally died. After the tow back to the slip we procedded to remove all fuel and added 10 gallons of new fuel. Monday I bled the system and it would do the same thing, loose rpm and die. Then noticed the fuel pump was not working, fiddled with the wiring and it would run intermittenly, then founf that there were two splices in the wiring to the control panel causing the problem. Replaced old untinned wire from ignition to pump with tinned copper wire. Now the rpm's without load will reach 3,000, under load only 1,900. Prior to this episode, rpm would reach 2,300 no load and 2,000 loaded. First I suspect dirty filter, water separator and maybe the line from the pump to the water separator may be restricted as it makes a severe curve and is somewhat flattened. I have not had any luck in draining the separator before but will try again this weekend then replace the primary filter. Another thought would be the fuel pump, a Facet 574A. It looks to be in fair shape and seems to work fine.
Last week when I responded below, my M25 was running great. Sunday we went out, windy, rough and I'm low on fuel. Before we could get the sails up the engine rpm started dropping and finally died. After the tow back to the slip we procedded to remove all fuel and added 10 gallons of new fuel. Monday I bled the system and it would do the same thing, loose rpm and die. Then noticed the fuel pump was not working, fiddled with the wiring and it would run intermittenly, then founf that there were two splices in the wiring to the control panel causing the problem. Replaced old untinned wire from ignition to pump with tinned copper wire. Now the rpm's without load will reach 3,000, under load only 1,900. Prior to this episode, rpm would reach 2,300 no load and 2,000 loaded. First I suspect dirty filter, water separator and maybe the line from the pump to the water separator may be restricted as it makes a severe curve and is somewhat flattened. I have not had any luck in draining the separator before but will try again this weekend then replace the primary filter. Another thought would be the fuel pump, a Facet 574A. It looks to be in fair shape and seems to work fine.
Some sources for replacment fuel pumps
for C30, C34 and C36 boats You may want to check the filter screen at the bottom of the old style pump if your plubming goes from the tank to the pump and then to the Racor primary.
for C30, C34 and C36 boats You may want to check the filter screen at the bottom of the old style pump if your plubming goes from the tank to the pump and then to the Racor primary.
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