We have had our 84 Hunter 31 for a year and a half now, which means I only have that much experince with a diesel engine. Something is not right, and I'm not sure what it is. Recently I removed my old Dahl Baldwin filter/water separator and per Steve Dion's recommendation installed a Racor 120 filter. Per another suggestion on this site I added a priming bulb between my fuel tank and the Racor filter so that I can bleed the filter after changing the element. I'm not sure if this is related to the problem I am now having. Before I replaced the filter, full throttle on my engine would run at about 2,000 to 2,100 rpms. That would get me up to about seven mph on my GPS. Now at full throttle my engine only runs at 1,200 rpm's. I am still getting up to 7 mph on the GPS, but with only 60% of the rpm's???? Additionally I am noticing some black smoke in the exhaust. Any ideas or suggestions about what is going on??? Thanks Joe S/V Charis
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Daniel Jonas
7 knots at 1200 rpm?
Joe, Are you sure that you are really only getting 1200 rpm's? I doubt that you could do 7 knots at that number of rpm's. The black smoke would indicate that you turning it too hard. I do not think that running at full throttle is appropriate. Perhaps the problem is in the tachometer. Dan Jonas (S/V Feije II)
Joe, Are you sure that you are really only getting 1200 rpm's? I doubt that you could do 7 knots at that number of rpm's. The black smoke would indicate that you turning it too hard. I do not think that running at full throttle is appropriate. Perhaps the problem is in the tachometer. Dan Jonas (S/V Feije II)
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Jim
Agree with Dan
It has to be your tach. Back off on the throttle to lose 1/2 a knot and your black smoke should disaper.
It has to be your tach. Back off on the throttle to lose 1/2 a knot and your black smoke should disaper.
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Joe Dickson
Yes 7 at 1,200...
As much as I tried to make sense of it I could not. I had not thought about the Tach being on the fritz. It is working, but perhaps there is something wrong with it and it is not reading correctly...
As much as I tried to make sense of it I could not. I had not thought about the Tach being on the fritz. It is working, but perhaps there is something wrong with it and it is not reading correctly...
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Rip Edmundson
2GM20F in 31 should get to at least 3400 RPM
2GM20F in 31 should get to at least 3400 RPM in full throttle. If it is not, you might want to check your exhaust elbow. However, if you are getting 7 knots, you are probably at full throttle no matter what your tach is saying. Check your tach first. Good luck
2GM20F in 31 should get to at least 3400 RPM in full throttle. If it is not, you might want to check your exhaust elbow. However, if you are getting 7 knots, you are probably at full throttle no matter what your tach is saying. Check your tach first. Good luck
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Kevin
Check the Tack
I would verify the engine rpms. As stated in another post a 2GM20 should get 3400 rpms, with the factory prop. Also I know placing a primer bulb inline is popular, but I have and wil,l most likely, not do it. The lift pump has a manual lever which works perfectly fine and doesn't add additonal sources of leaks ( air or fuel). Kevin
I would verify the engine rpms. As stated in another post a 2GM20 should get 3400 rpms, with the factory prop. Also I know placing a primer bulb inline is popular, but I have and wil,l most likely, not do it. The lift pump has a manual lever which works perfectly fine and doesn't add additonal sources of leaks ( air or fuel). Kevin
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Bill O'Donovan
Two points
I'm with Rip about the exhaust elbow, for it is the single biggest culprit in situations like yours. Has the elbow been replaced in the past five years? If not, go for it. Your marina probably has one in stock, since they have to be replaced so frequently. Previous posts have decrie the priming bulb as dangerous because it will deteriorate and send particles of rubber through the engine, to great harm. My preferred method is to fill the filter bowls as best I can before screwing back on. That makes for fewer pushes on the primer tab.
I'm with Rip about the exhaust elbow, for it is the single biggest culprit in situations like yours. Has the elbow been replaced in the past five years? If not, go for it. Your marina probably has one in stock, since they have to be replaced so frequently. Previous posts have decrie the priming bulb as dangerous because it will deteriorate and send particles of rubber through the engine, to great harm. My preferred method is to fill the filter bowls as best I can before screwing back on. That makes for fewer pushes on the primer tab.
Something up with your tach.
Joe: There is something up with your tach. Like Rip E. said you should be able to get 3400+ out the engine in NEUTRAL. The engine is rated to run up to 3850+ without a load. I would check the pickup and see if it is shorting first. If you are running 7kts it sounds like the engine is running fine (with or without your new filter <g>). You also want to check your prop to see if this is causing some of your black smoke. The previous advice about the elbow is also a good source of smoking. If you are no comfortable doing some of this yourself, you may check with a mechanic. They have a special device that they can check the engine RPMs. But you should just take the lead off and make sure that it is clean and secure. Then check the panel and make sure that the wire is also secure on it too. Use a little dielectric grease on the contacts after you clean them up.
Joe: There is something up with your tach. Like Rip E. said you should be able to get 3400+ out the engine in NEUTRAL. The engine is rated to run up to 3850+ without a load. I would check the pickup and see if it is shorting first. If you are running 7kts it sounds like the engine is running fine (with or without your new filter <g>). You also want to check your prop to see if this is causing some of your black smoke. The previous advice about the elbow is also a good source of smoking. If you are no comfortable doing some of this yourself, you may check with a mechanic. They have a special device that they can check the engine RPMs. But you should just take the lead off and make sure that it is clean and secure. Then check the panel and make sure that the wire is also secure on it too. Use a little dielectric grease on the contacts after you clean them up.
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Duane Cady
Is it possible ?
What kind of RPMs do you get in neutral ? Is it possible that you have a fouled or over-pitched prop that woould cause low RPMs, and black smoke at high power ? As stated in other posts, my yanmar gets 3400 RPM, and cruises at 6 knots at 2700-2900 rpms. Duane
What kind of RPMs do you get in neutral ? Is it possible that you have a fouled or over-pitched prop that woould cause low RPMs, and black smoke at high power ? As stated in other posts, my yanmar gets 3400 RPM, and cruises at 6 knots at 2700-2900 rpms. Duane
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Joe Dickson
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