Have a problem with Yanmar 2GM20F overheating. Replaced raw water filter unit, impeller, thermostat, flushed fresh water side, antifreeze, belts
- Status
- Not open for further replies.
Check you mixing elbow and hoses.
Norm: Check the hoses from the raw water strainer to the mixing elbow. Make sure that the hoses are not collapsing when when it is sucking raw water. Then you need to check out the mixing elbow. If you are overheating at the higher RPM's it is a good chance that the elbow is the problem.
Norm: Check the hoses from the raw water strainer to the mixing elbow. Make sure that the hoses are not collapsing when when it is sucking raw water. Then you need to check out the mixing elbow. If you are overheating at the higher RPM's it is a good chance that the elbow is the problem.
S
Steve O.
overheat
My '88 33.5 with 2GM will cruise all day long at 2800 but if I push it to 3200 I get an alarm. Possible coked exhaust elbow?
My '88 33.5 with 2GM will cruise all day long at 2800 but if I push it to 3200 I get an alarm. Possible coked exhaust elbow?
R
Ron Hughes
one last place you might look......
Norm, last Summer we had a real problem with white smoke in our exaust aboard our '94 40.5 (4 cyl. 50 h.p. Yanmar YJH2E). We had a moderate overheating problem as well. After 2 days of waiting for the mechanic, etc. etc. I finally started at the very beginning to fix the problem. That's where it was! A large piece of sea grass had lodged in the hose between the thru-hull and the elbow AHEAD of the raw water strainer!(The 90 degree turn at the elbow was too sharp for it to pass) Just remove the hose at the raw water strainer and open the thru-hull to check it. If you've checked all of the other stuff, I'll bet that this is your fix. Good Luck! Ron Hughes s/v "Best Revenge" H 40.5
Norm, last Summer we had a real problem with white smoke in our exaust aboard our '94 40.5 (4 cyl. 50 h.p. Yanmar YJH2E). We had a moderate overheating problem as well. After 2 days of waiting for the mechanic, etc. etc. I finally started at the very beginning to fix the problem. That's where it was! A large piece of sea grass had lodged in the hose between the thru-hull and the elbow AHEAD of the raw water strainer!(The 90 degree turn at the elbow was too sharp for it to pass) Just remove the hose at the raw water strainer and open the thru-hull to check it. If you've checked all of the other stuff, I'll bet that this is your fix. Good Luck! Ron Hughes s/v "Best Revenge" H 40.5
P
Paul Akers
Good find, Ron
The same thing hapened to me a couple of years ago except the mechanic already looked at it. He had left for a little while and I that's when I found it. Darn 90 degree strainer elbows will get you every time. It has happened to me several times since then. The trick is to understand how much water passes through the engine and pay close attention while it is running to watch for changes.
The same thing hapened to me a couple of years ago except the mechanic already looked at it. He had left for a little while and I that's when I found it. Darn 90 degree strainer elbows will get you every time. It has happened to me several times since then. The trick is to understand how much water passes through the engine and pay close attention while it is running to watch for changes.
R
Ron Hughes
last place to look.......
I forgot to mention that I replaced my tight elbows with gentle 90 degree elbows to prevent recurrance of the problem. Too bad they don't come that way......... Ron
I forgot to mention that I replaced my tight elbows with gentle 90 degree elbows to prevent recurrance of the problem. Too bad they don't come that way......... Ron
J
John Van Wagoner
Engine overheating
I had the same problem on a previous boat with a yanmar engine exactly like yours. I checked EVERYTHING except the mixing elbow. And that was where the problem was, sort of. Specifically, the fitting at the top of the elbow connected to the raw water hose coming out of the heat exchanger was plugged with scale.Only a small opening was left inside this L-shaped fitting (it is threaded into the elbow).At low rpms the opening was large enough to allow the water to flow out of the heat exchanger into the elbow. At higher rpms (> 2500-2800) the hole was not large enough to allow all the water to pass through. Back pressure in the hose to the heat exchanger built up and the flow out of the heat exchanger stopped and the engine overheated. One time the pressure got so large that it blew the hose off of the connection to the heat exchanger on the top of the engine. What a mess. So, just remove the hose at the fitting on the heat exchanger and make sure it is not plugged with scale. Simple to do and I am pretty sure it is a common cause of engine overheating under the conditions you describe. BTW, it is a good idea to add this to an annual engine inspection. If your engine is more than years old you probably have scale there even if it isn't part of the problem.
I had the same problem on a previous boat with a yanmar engine exactly like yours. I checked EVERYTHING except the mixing elbow. And that was where the problem was, sort of. Specifically, the fitting at the top of the elbow connected to the raw water hose coming out of the heat exchanger was plugged with scale.Only a small opening was left inside this L-shaped fitting (it is threaded into the elbow).At low rpms the opening was large enough to allow the water to flow out of the heat exchanger into the elbow. At higher rpms (> 2500-2800) the hole was not large enough to allow all the water to pass through. Back pressure in the hose to the heat exchanger built up and the flow out of the heat exchanger stopped and the engine overheated. One time the pressure got so large that it blew the hose off of the connection to the heat exchanger on the top of the engine. What a mess. So, just remove the hose at the fitting on the heat exchanger and make sure it is not plugged with scale. Simple to do and I am pretty sure it is a common cause of engine overheating under the conditions you describe. BTW, it is a good idea to add this to an annual engine inspection. If your engine is more than years old you probably have scale there even if it isn't part of the problem.
- Status
- Not open for further replies.