I recently purchased a boat with a D50 engine. The engines had water in the oil (a lot!) for 1-2 years, and before use we had the cyl head off and overhauled it, and replaced the cooler (wich was the cause of the water in the engine).
When we tried to start it the first time, the bloody thing started on the first rev. It then virtually exploded up to ~5000 RPM, and we had no way to stop it. Pulling the stop wire made no difference, and the accel lever was in Idle. We finally reduced the RPM`s to 3000 or so by blocking the air supply by hand, and stopped it by cutting off the diesel supply.
We then started dissassembling the pumps,. guvernor lever etc etc. The lever was stuck due to rust, so we put everything, including the crankcase in diesel for a week. We then inspected and reassembled everything, zeroed the pumps and so on. As far as we could see, everything was in top condition. The only thing we did was to release that little piston on the pump-camshaft that was stuck.
So we started the engine again, and this time it worked fine. At this time we had the boat on shore, so we connected a water hose, and let it idle for an hour or so. At this point, we could use the throttle as normal, rev it to 2-3000 and back down with no problems at all.
Then we changed the oil, put the boat back on the sea, and stared it again.... And once again, the bloody thing revved out on us, luckily we were prepared and choked it on the air supply. Pulling the stop did not stop it, but choking it while pulling the stop helped. So, once more, everything into pieces, inspect, and reinstall. Nothing appeard unnormal at this point. The piston was in the rearmost position, not stuck in the front position like the last time, and everything moves perfectly as far as we can tell.
So now, we have tried, disassembled and reassembled at least 15 times. Still it revs out. Could someone please help us understand how the throttle system works on these engines, so we can troubleshoot it? Any ideas on what can be wrong on this engine?
Thanks.
When we tried to start it the first time, the bloody thing started on the first rev. It then virtually exploded up to ~5000 RPM, and we had no way to stop it. Pulling the stop wire made no difference, and the accel lever was in Idle. We finally reduced the RPM`s to 3000 or so by blocking the air supply by hand, and stopped it by cutting off the diesel supply.
We then started dissassembling the pumps,. guvernor lever etc etc. The lever was stuck due to rust, so we put everything, including the crankcase in diesel for a week. We then inspected and reassembled everything, zeroed the pumps and so on. As far as we could see, everything was in top condition. The only thing we did was to release that little piston on the pump-camshaft that was stuck.
So we started the engine again, and this time it worked fine. At this time we had the boat on shore, so we connected a water hose, and let it idle for an hour or so. At this point, we could use the throttle as normal, rev it to 2-3000 and back down with no problems at all.
Then we changed the oil, put the boat back on the sea, and stared it again.... And once again, the bloody thing revved out on us, luckily we were prepared and choked it on the air supply. Pulling the stop did not stop it, but choking it while pulling the stop helped. So, once more, everything into pieces, inspect, and reinstall. Nothing appeard unnormal at this point. The piston was in the rearmost position, not stuck in the front position like the last time, and everything moves perfectly as far as we can tell.
So now, we have tried, disassembled and reassembled at least 15 times. Still it revs out. Could someone please help us understand how the throttle system works on these engines, so we can troubleshoot it? Any ideas on what can be wrong on this engine?
Thanks.