We have a new 33 with a Yanmar 3YM30 engine. The operators manual indicates 3600RPM, but the Yanmar Tach reads much higher. I do not have the 3 blade prop. I have used 3200 RPM as safe and except for the wrong belt, it seems to be safe. I see in the review by John Driscoll, his overheats at 2500. Does anyone else have any info? Yanmar said that Hunter should have information concerning this issue, but I have not been able to contact them yet about this issue.
Safe cruising RPM
- Thread starter JohnEh
- Start date
- Status
Operating RPM
John, I've seen several of your posts, these are some great questions for a new owner. Yanmar engines LIKE to be worked. Cruise at 70-85% power or 2500 to 3200. the tach graduated higher incase of an overrev (unlikely) so you have some idea. If you are idleing to warm up or charge batteries. Drop it in gear and GENTLY pull on the ropes or anchor. minimize the time the engine runs at low speed or unloaded, it builds carbon in the head and exhaust. I strongly recomend you contact the distributer for you are and take an owners course. Pat McCartin Inland Marine Diesel Buford, Ga imd_ga@hotmail.com
John, I've seen several of your posts, these are some great questions for a new owner. Yanmar engines LIKE to be worked. Cruise at 70-85% power or 2500 to 3200. the tach graduated higher incase of an overrev (unlikely) so you have some idea. If you are idleing to warm up or charge batteries. Drop it in gear and GENTLY pull on the ropes or anchor. minimize the time the engine runs at low speed or unloaded, it builds carbon in the head and exhaust. I strongly recomend you contact the distributer for you are and take an owners course. Pat McCartin Inland Marine Diesel Buford, Ga imd_ga@hotmail.com
3ym39
I have the same engine in my H-36. I have run over 45 KM @3200 RPM. This gives me a speed just over 6 knots on flat water no problems. According to the manual I should use 4 liters a hour. At 2500 RPM I make just over 5 Knots. This should require only 2 liters a hour just about doubling ones range. I have none this with a two bladed prop. Boat does slow with waves but waves usually mean wind and the engine gets turned off.
I have the same engine in my H-36. I have run over 45 KM @3200 RPM. This gives me a speed just over 6 knots on flat water no problems. According to the manual I should use 4 liters a hour. At 2500 RPM I make just over 5 Knots. This should require only 2 liters a hour just about doubling ones range. I have none this with a two bladed prop. Boat does slow with waves but waves usually mean wind and the engine gets turned off.
John, got 3 blade on 3gm30
I run mine @ 2800rpm for 6.5kts or 2000rpm just loafing. Just figured out fuel this last weekend and getting .5gal/hr over 51hrs engine time. Engine seems to like the 2800 with the 3 blade prop very smooth. Hope this helps Jim S/V Java
I run mine @ 2800rpm for 6.5kts or 2000rpm just loafing. Just figured out fuel this last weekend and getting .5gal/hr over 51hrs engine time. Engine seems to like the 2800 with the 3 blade prop very smooth. Hope this helps Jim S/V Java
Happy with my engine
I have not had all the same issues as you have, so my entry is a bit limited. I have over 150 NM on my H33, but very little engine hours. The engine is the 30 HP, and I have a 3 bladed prop. I run at 2400 rpm for putting and 3200-3400 for real movement. I have no fear of bumping the engine (4000 or so rpm) when docking. All in all, the engine is perfect and at these rpms I have not encountered any issues that caused me concern. Initially the admiral felt I was going too fast so we would go at 2700 rpm until she went down below or looked away
I have not had all the same issues as you have, so my entry is a bit limited. I have over 150 NM on my H33, but very little engine hours. The engine is the 30 HP, and I have a 3 bladed prop. I run at 2400 rpm for putting and 3200-3400 for real movement. I have no fear of bumping the engine (4000 or so rpm) when docking. All in all, the engine is perfect and at these rpms I have not encountered any issues that caused me concern. Initially the admiral felt I was going too fast so we would go at 2700 rpm until she went down below or looked away
One vote for 3200rpm
I have experimented with different rates. I have found my engine is happiest at about 3100-3200 rpm. Above that and I have experienced overheating once (trying to race a thunderstom to a safe port). Below that and I worry about carbon buildup. Andy
I have experimented with different rates. I have found my engine is happiest at about 3100-3200 rpm. Above that and I have experienced overheating once (trying to race a thunderstom to a safe port). Below that and I worry about carbon buildup. Andy
- Status