What is the highest rpm I can cruise at without over heating I have a 2 cylinder diesel on my 1991 h30
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That depends...
You probably have the 2GM20F 18hp Yanmar. If so, MAX RPM is about 3400..BUT you should NEVER run at that speed for more than 30-40 minutes or you take a chance on over-heating and causinng $$$$$ damage. Your power curve is probably best at about 2,750 rpm or so. She'll run all day at that speed and never breathe hard. Also, the hull speed gained at 3400 vs 2750 is negligeable. You can also check your Yanmar owners manual for additional info on that.
You probably have the 2GM20F 18hp Yanmar. If so, MAX RPM is about 3400..BUT you should NEVER run at that speed for more than 30-40 minutes or you take a chance on over-heating and causinng $$$$$ damage. Your power curve is probably best at about 2,750 rpm or so. She'll run all day at that speed and never breathe hard. Also, the hull speed gained at 3400 vs 2750 is negligeable. You can also check your Yanmar owners manual for additional info on that.
WOT?
The test is in the doing of course as an engine with cooling problems well, has problems. Given that, you should be able to run at WOT all day long and not overheat. I'd recommend 85-90% throttle as a cruising RPM so as not to carbon up the engine. Diesels can take the higher power outputs due to their heaver construction. You get there faster too.
The test is in the doing of course as an engine with cooling problems well, has problems. Given that, you should be able to run at WOT all day long and not overheat. I'd recommend 85-90% throttle as a cruising RPM so as not to carbon up the engine. Diesels can take the higher power outputs due to their heaver construction. You get there faster too.
Like I said...
Check your owner's manual. It'll describe the most fuel efficient speed for the fuel consumed. Also, follow the link below to a site on the 2GM20F...click on the "Brochure" link to get to the various charts and performance measurements.
Check your owner's manual. It'll describe the most fuel efficient speed for the fuel consumed. Also, follow the link below to a site on the 2GM20F...click on the "Brochure" link to get to the various charts and performance measurements.
Depends on the motor....
It depends on your motor, but Yanmar recommends 70-80% of the max rated RPM. This is their recommended cruising RPM. If you have a GM power plant the max rating is 3600 rpm so the max cruising RPM would be about 2900. None of this means anything if you do not have the correct prop, clean prop, shaft and bottom. If you have excessive fouling your will probably start blowing black smoke prior to the over-heat sensor to go off.
It depends on your motor, but Yanmar recommends 70-80% of the max rated RPM. This is their recommended cruising RPM. If you have a GM power plant the max rating is 3600 rpm so the max cruising RPM would be about 2900. None of this means anything if you do not have the correct prop, clean prop, shaft and bottom. If you have excessive fouling your will probably start blowing black smoke prior to the over-heat sensor to go off.
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