I'm only getting around 2400 RPM's on my Yanmar 2GMF. It is the same whether I'm in neutral or in forward gear so it has nothing to do with the prop. The smooth spot is around 1900 RPM. This gives me about 5.7 kts on my 1984 Hunter 31. Filters have been changed recently. Any ideas would be greatly appreciated Thanks Steve
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A Couple of Ideas
I have the same engine on my boat and I have a problem sometimes that the the Tach cable may be slipping or not reading corectly (it seems to jump around sometimes). Also you may want to open the engine compartment, run the engine in neutral, have someone on deck read the Tach, and depress the throttle linkage manually as far as it will go. If you get 3300 - 3600 RPMs then yo need to adjust the throttle cable. Mike
I have the same engine on my boat and I have a problem sometimes that the the Tach cable may be slipping or not reading corectly (it seems to jump around sometimes). Also you may want to open the engine compartment, run the engine in neutral, have someone on deck read the Tach, and depress the throttle linkage manually as far as it will go. If you get 3300 - 3600 RPMs then yo need to adjust the throttle cable. Mike
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Pat McCartin
A common problem
Steve, This is the symptoms of a very common problem. The exhaust elbow is probably coked up and increasing back pressure on the engine. Remember, an engine is an air pump. Air in must equal air out. Otherwise performance is comprimised. Pat McCartin Inland Marine Diesel Buford, GA imd_ga@hotmail.com
Steve, This is the symptoms of a very common problem. The exhaust elbow is probably coked up and increasing back pressure on the engine. Remember, an engine is an air pump. Air in must equal air out. Otherwise performance is comprimised. Pat McCartin Inland Marine Diesel Buford, GA imd_ga@hotmail.com
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Bill O'Donovan
If it's the mixing elbow...
...you have to remove it by removing the manifold to which it's attached. Those four bolts are accessible, while the big bolt for the elbow is not. When you get them apart (may take a machine shop with a blow torch) just buy a new elbow for $150. Not worth trying to blow out the hardened carbon. Many ship stores carry the elbow, because coking up is so frequent. You'll breathe easier, as will the 2GM.
...you have to remove it by removing the manifold to which it's attached. Those four bolts are accessible, while the big bolt for the elbow is not. When you get them apart (may take a machine shop with a blow torch) just buy a new elbow for $150. Not worth trying to blow out the hardened carbon. Many ship stores carry the elbow, because coking up is so frequent. You'll breathe easier, as will the 2GM.
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Rick J
I'm not sure, but...
In the absence of any overheating issues, I'm not sure it's your mixing elbow. The part of the mixing elbow that gets plugged first is generally the small diameter portion that allows the raw water to exit from the heat exchanger... the engine exhaust goes through the large-bore part, which would be less prone to becoming stenotic because of it's large diameter. Certainly not impossible, though. Anyway, I replaced my mixing elbow a couple of years ago because of an overheating problem. Not much fun, but certainly DIY. You'll have the scars to prove your courage. But RPM issues might conceivably be the result of the throttle cable, or the governor, which are more accessible, to a certain extent. I would try to control the rpm directly from the throttle cable attachment at the engine, and then give some thought to the governor, before changing the mixing elbow. On the other hand, sooner or later it will need to be replaced, and these guys who have already responded to you post obviously have valid points of view. Good luck... RJ
In the absence of any overheating issues, I'm not sure it's your mixing elbow. The part of the mixing elbow that gets plugged first is generally the small diameter portion that allows the raw water to exit from the heat exchanger... the engine exhaust goes through the large-bore part, which would be less prone to becoming stenotic because of it's large diameter. Certainly not impossible, though. Anyway, I replaced my mixing elbow a couple of years ago because of an overheating problem. Not much fun, but certainly DIY. You'll have the scars to prove your courage. But RPM issues might conceivably be the result of the throttle cable, or the governor, which are more accessible, to a certain extent. I would try to control the rpm directly from the throttle cable attachment at the engine, and then give some thought to the governor, before changing the mixing elbow. On the other hand, sooner or later it will need to be replaced, and these guys who have already responded to you post obviously have valid points of view. Good luck... RJ
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Pat McCartin
Yanmar Govenors
The Govenor assenply is completly contained within the front cover of the engine. There is an adjustment that is external BUT it is factory sealed at factory after the test run. Please don't adjust it, it can lead to problems down the road. I'd first pull off the exhaust riser and inspect it. The job requires, a screw driver for the hose clamps and a 12 or 13 mm socket. It should take all of a 1/2 hour to remove the elbow and inspect it. Pat McCartin Inland Marine Diesel Buford, GA imd_ga@hotmail.com
The Govenor assenply is completly contained within the front cover of the engine. There is an adjustment that is external BUT it is factory sealed at factory after the test run. Please don't adjust it, it can lead to problems down the road. I'd first pull off the exhaust riser and inspect it. The job requires, a screw driver for the hose clamps and a 12 or 13 mm socket. It should take all of a 1/2 hour to remove the elbow and inspect it. Pat McCartin Inland Marine Diesel Buford, GA imd_ga@hotmail.com
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Steve
Thanks for the info
Thanks for the replys. I checked the trottle cable on the engine side and the lever is open as far as it will go. I'm thinking injector problems. Have not checked the mixing elbow yet. I guess that's the first place to start. Steve
Thanks for the replys. I checked the trottle cable on the engine side and the lever is open as far as it will go. I'm thinking injector problems. Have not checked the mixing elbow yet. I guess that's the first place to start. Steve
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