We are now optimistic that the overheating problem on our engine has been resolved. The engine ran hot and the overheat alarm (212 degrees) would come on at 3000 rpm or less. The manual says that you should be able to cruise at 3400 rpm or less for 9 out of 10 hours and run full throttle (4050) for 30 minutes. All of the easy checks were made; impeller/belts/coolant/alarm sensor/etc. Everything checked out. Finally, our Yanmar dealer took the heat exchanger off and discovered what he beleived to be cosmoline on the coils. After cleaning the coils and also replacing the thermostat and flushing the whole system, the engine performs great. We now have a temperature guage on the panel next to the tach. At full throttle, the temperature does not go over 180 degrees and while cruising at 3400 the heat never went over 170 and at 3200 the heat was not over 160. These reading were while motor sailing between Slidell, LA and Biloxi, MS( a distance of 55-60 nautical miles each way). The seawater temp was 84-90 degrees. In addition, now there is little or no diesel odor in the cabin during or after running the engine. At this point, we are monitoring our fuel tank. The capacity is suppose to be 25 gallons. However, when we filled up, we took about 25.5 gallons. Any comments are always welcome.
Yanmar 3YM30
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Good news John
Hope that was the cure. What is cosmoline and how/why did it get there? Now hopefully you can get out and enjoy that boat. I was out a few days ago - made 7.6 knots in a 17 knot breeze. Great fun. Now if the weather would just clear up and act like it's May instead of February!
Hope that was the cure. What is cosmoline and how/why did it get there? Now hopefully you can get out and enjoy that boat. I was out a few days ago - made 7.6 knots in a 17 knot breeze. Great fun. Now if the weather would just clear up and act like it's May instead of February!
M
Michael
RE: Yanmar 3ym30 Temperatures
John, How did you know the temperatures that your engine was running at the various RPM's? Do you have a temperature gauge? I wish my H33 had a temperature gauge instead of the idiot light... Michael
John, How did you know the temperatures that your engine was running at the various RPM's? Do you have a temperature gauge? I wish my H33 had a temperature gauge instead of the idiot light... Michael
J
John G.
3YM30 Water Temperature Gauge a Great Idea
John: Now that you have an engine water temperature gauge installed, did you also retain your temp alarm and panel overheat light or did you replace them with the temp gauge? Is there sufficient space behind the cockpit engine panel to accommodate a (2-inch)temp gauge? Someone told me if I wanted both alarm and gauge I would require a "T" joint to accommodate the two senders? If in fact you retained the two systems whose gauge/sender combination did you use? Can you let me know the supplier for the the temp gauge sender and "T" joint. I discussed the matter with our local Yanmar dealer and it was like pulling the proverbial "hen's teeth". They were certainly not helpful. They think it is unnecessary to have both an alarm and a temp gauge. Having had heating problems with my 3YM30 I would feel better monitoring the water temperature and not have to wait till the alarm is screaming at me to stop! I look forward to your reply. You can also email me directly at jegiraudy@aol.com
John: Now that you have an engine water temperature gauge installed, did you also retain your temp alarm and panel overheat light or did you replace them with the temp gauge? Is there sufficient space behind the cockpit engine panel to accommodate a (2-inch)temp gauge? Someone told me if I wanted both alarm and gauge I would require a "T" joint to accommodate the two senders? If in fact you retained the two systems whose gauge/sender combination did you use? Can you let me know the supplier for the the temp gauge sender and "T" joint. I discussed the matter with our local Yanmar dealer and it was like pulling the proverbial "hen's teeth". They were certainly not helpful. They think it is unnecessary to have both an alarm and a temp gauge. Having had heating problems with my 3YM30 I would feel better monitoring the water temperature and not have to wait till the alarm is screaming at me to stop! I look forward to your reply. You can also email me directly at jegiraudy@aol.com
J
John Blakely
3YM30
John and others with the 3YM30. I just repowered my 1985 Hunter 31 with a Yanmar 3YM30. So far, the engine is excellent. My manual says that top RPM is 3600 although I have briefly run it at 3900. John, you mentioned that you have run yours at 4050 and cruise at 3400. I am used to a 20 year old Yanmar with only 13 hp so I am not used to the new engine yet. Could you tell me where your manual the specs came from? I seem to have to run it around 3000 or so to get 6.7 (hull speed) so, I'd like to add on comfortably another 100 or so since I frequently coastal cruise for 6 or 8 hrs at a time if the wind is low. Also, from the other posts, it seems that some engines had an overheating problem; if so, could you refer me to a source to learn more. Thanks in advance for all your efforts. John Blakely
John and others with the 3YM30. I just repowered my 1985 Hunter 31 with a Yanmar 3YM30. So far, the engine is excellent. My manual says that top RPM is 3600 although I have briefly run it at 3900. John, you mentioned that you have run yours at 4050 and cruise at 3400. I am used to a 20 year old Yanmar with only 13 hp so I am not used to the new engine yet. Could you tell me where your manual the specs came from? I seem to have to run it around 3000 or so to get 6.7 (hull speed) so, I'd like to add on comfortably another 100 or so since I frequently coastal cruise for 6 or 8 hrs at a time if the wind is low. Also, from the other posts, it seems that some engines had an overheating problem; if so, could you refer me to a source to learn more. Thanks in advance for all your efforts. John Blakely
J
John
Update
We arenow in Gainsville and plan to visit Hunter Marine tomorrow. The Yanmar dealer in LA installed the temperature guage and has indicated that the alarm is still functional(heat must rise to 212 degrees). With the guage, hopefully this will never happen. I will try to find out exactly what he installed. I have a picture which I took today and I will try to post it after our visit to Hunter. Saturday, we are off to St. Thomas(On Carnival Cruise Line). As far as the rpm, the instructions are in the owner's manual close to the beginning. The manual states that you should run the engine at max at least once a month in order to blow out the deposits.
We arenow in Gainsville and plan to visit Hunter Marine tomorrow. The Yanmar dealer in LA installed the temperature guage and has indicated that the alarm is still functional(heat must rise to 212 degrees). With the guage, hopefully this will never happen. I will try to find out exactly what he installed. I have a picture which I took today and I will try to post it after our visit to Hunter. Saturday, we are off to St. Thomas(On Carnival Cruise Line). As far as the rpm, the instructions are in the owner's manual close to the beginning. The manual states that you should run the engine at max at least once a month in order to blow out the deposits.
Different RPM's
I would think that different max/cruising engine RPM's are probably related to what type of prop you have. Different number of blades and their pitch can place different loads on the engine. I have a three blade from the factory. If I ran at 3400-3600 I would overheat fairly quickly. I typically run more around 2800-3000, and occasionaly a little higher. Basically I run the engine up until I reach hull speed, any additional RPM's would only allow for minimal gains in speed - and at the price for fuel these days...
I would think that different max/cruising engine RPM's are probably related to what type of prop you have. Different number of blades and their pitch can place different loads on the engine. I have a three blade from the factory. If I ran at 3400-3600 I would overheat fairly quickly. I typically run more around 2800-3000, and occasionaly a little higher. Basically I run the engine up until I reach hull speed, any additional RPM's would only allow for minimal gains in speed - and at the price for fuel these days...
J
John
3 Blade Prop
We have a new 3 blade prop on our boat which was overheating before the discovery of the cosmoline in the heat exchanger. Now we can get max rpm at 180 degrees or less and no overheating. Maybe your boat also has cosmoline in the heat exchanger. Running cool is much better for us.
We have a new 3 blade prop on our boat which was overheating before the discovery of the cosmoline in the heat exchanger. Now we can get max rpm at 180 degrees or less and no overheating. Maybe your boat also has cosmoline in the heat exchanger. Running cool is much better for us.
H
Holland
Us too
John. We are chasing the same problem on our 2004 33. Just had a gauge installed which confirmed the overheat alarm was correct. It happens at 2500 rpms and over. We have changed the impeller and thermostat, but it still happens. So frustrating on a new boat. Hunter told us about your problem yesterday and said you were at the factory recently. Did yanmar help your dealer figure it out and did they pay for the work under warranty? We have had a number of smaller problems with this boat but this is a big one.
John. We are chasing the same problem on our 2004 33. Just had a gauge installed which confirmed the overheat alarm was correct. It happens at 2500 rpms and over. We have changed the impeller and thermostat, but it still happens. So frustrating on a new boat. Hunter told us about your problem yesterday and said you were at the factory recently. Did yanmar help your dealer figure it out and did they pay for the work under warranty? We have had a number of smaller problems with this boat but this is a big one.
D
Donald
3ym30 temp gauge
Holland, Could you give us some details about the gauge that was installed? John has posted numerous times about the improvements he makes, but will not give details. Thanks Donald
Holland, Could you give us some details about the gauge that was installed? John has posted numerous times about the improvements he makes, but will not give details. Thanks Donald
J
John
Details
Yes our problem is suppose to be covered by the Yanmar warranty. If the heat exchanger was assembled on the engine without properly removing cosmoline, the cooling will not work properly. Our Yanmar dealer had never seen anything like this and thought that it may have been an oversight on our engine only. However, if you are having the same trouble, I would recommend contacting Hunter to follow up with Yanmar on taking the heat exchanger off and checking to make sure there is no cosmoline or other substance which is rendering the exchanger unable to cool.
Yes our problem is suppose to be covered by the Yanmar warranty. If the heat exchanger was assembled on the engine without properly removing cosmoline, the cooling will not work properly. Our Yanmar dealer had never seen anything like this and thought that it may have been an oversight on our engine only. However, if you are having the same trouble, I would recommend contacting Hunter to follow up with Yanmar on taking the heat exchanger off and checking to make sure there is no cosmoline or other substance which is rendering the exchanger unable to cool.
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