Hi Group...
I am out of ideas why my Westerbeke 21a on Tern will not hold a constant rpm at full throttle. The engine slowly occillates between 2500rpm and 3000rpm at full throttle (in gear going forward). Most of the time it holds between 2500 and 2600 and occasionally will speed up to 3000.
The prop is clean, the filters were changed 6 months ago with few hours on them. The bowl at the bottom of the Racor is clean with just a tiny amout of sediment. I am meticulous with BioBor and Diesel "start and stor". The tank was topped off in August with about 12 gallons. She starts well and doesnt smoke except for a little grey smoke at full throttle.
Does anyone have a suggestion what to check next?
Thanks Boyd
tern30@aol.com
Diesel engine rpm problem
Moderator: Jim Walsh
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Larry DeMers
Re: Diesel engine rpm problem
Sounds like the governor is not reacting right. Is there a correspnding engine sound change along with the tach. indication? That would eliminate just a tach problem then (otherwise, check for loose or dirty tach connections on engine).
Larry DeMers
s/v DeLaMer
CD 30
demers@sgi.com
Larry DeMers
s/v DeLaMer
CD 30
Boyd wrote: Hi Group...
I am out of ideas why my Westerbeke 21a on Tern will not hold a constant rpm at full throttle. The engine slowly occillates between 2500rpm and 3000rpm at full throttle (in gear going forward). Most of the time it holds between 2500 and 2600 and occasionally will speed up to 3000.
The prop is clean, the filters were changed 6 months ago with few hours on them. The bowl at the bottom of the Racor is clean with just a tiny amout of sediment. I am meticulous with BioBor and Diesel "start and stor". The tank was topped off in August with about 12 gallons. She starts well and doesnt smoke except for a little grey smoke at full throttle.
Does anyone have a suggestion what to check next?
Thanks Boyd
demers@sgi.com
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Joe Mac Phee
Re: Diesel engine rpm problem
Boyd,
If the engine surges so that the RPM set point always goes up and then returns, consider whether the transmission could be slipping intermittently. If the transmission slips, it will unload the engine and increase the RPM until the governor can recover and/or the transmission grabs again. Any noticeable change in your forward progress when experiencing this phenomenon?
Good luck,
Joe Mac Phee
S/V Iolanthe
CD-30/K
jvmacphee@aol.com
If the engine surges so that the RPM set point always goes up and then returns, consider whether the transmission could be slipping intermittently. If the transmission slips, it will unload the engine and increase the RPM until the governor can recover and/or the transmission grabs again. Any noticeable change in your forward progress when experiencing this phenomenon?
Good luck,
Joe Mac Phee
S/V Iolanthe
CD-30/K
jvmacphee@aol.com
-
Boyd
Re: Diesel engine rpm problem
Yes there is a perceptable change in engine sound indicating that the rpm is really changing. The fan belt is tight. I will check the alternator connections tonight. I dont have access to a mechanical tach as of now.
Tern30@aol.com
Larry DeMers wrote: Sounds like the governor is not reacting right. Is there a correspnding engine sound change along with the tach. indication? That would eliminate just a tach problem then (otherwise, check for loose or dirty tach connections on engine).
Larry DeMers
s/v DeLaMer
CD 30
Boyd wrote: Hi Group...
I am out of ideas why my Westerbeke 21a on Tern will not hold a constant rpm at full throttle. The engine slowly occillates between 2500rpm and 3000rpm at full throttle (in gear going forward). Most of the time it holds between 2500 and 2600 and occasionally will speed up to 3000.
The prop is clean, the filters were changed 6 months ago with few hours on them. The bowl at the bottom of the Racor is clean with just a tiny amout of sediment. I am meticulous with BioBor and Diesel "start and stor". The tank was topped off in August with about 12 gallons. She starts well and doesnt smoke except for a little grey smoke at full throttle.
Does anyone have a suggestion what to check next?
Thanks Boyd
Tern30@aol.com
-
Boyd
Re: Diesel engine rpm problem
Thanks Joe...I have not been aware of a change in boat speed but will check it out next time I get out. The rpms cycle faster and slower fairly slowly and the engine seems to be struggling to make 3000 rpm. Never holding it for long before falling back to 2500. I talked with the Westerbeke distributor and he suggested changing the filters again and if that doesnt help remove the injectors and have them tested. I will inquire about testing the transmission also. Hadnt thought of that one.
Tern30@aol.com
Joe Mac Phee wrote: Boyd,
If the engine surges so that the RPM set point always goes up and then returns, consider whether the transmission could be slipping intermittently. If the transmission slips, it will unload the engine and increase the RPM until the governor can recover and/or the transmission grabs again. Any noticeable change in your forward progress when experiencing this phenomenon?
Good luck,
Joe Mac Phee
S/V Iolanthe
CD-30/K
Tern30@aol.com
-
Larry DeMers
Re: Diesel engine rpm problem
Boyd,
This sounds like a governor problem. Sometimes these mechanical devices get crudded over and stick. Question: When the engine starts to change rpm on you, does it do so once and stay at the new rpm, or will it work up then work down the rpm scale? Does it randomly do this? Or is it repeatable at a specific rpm? Other possible causes would be the injector pumps metering section. If the metering mechanism is fouled, it will regulate fuel unevenly, resulting in the rpm wandering.
Does this happen at lower rpm at all? Do you use 2500 rpm much? (2600 rpm is the max rpm the MD7B is supposed to see, so I would not run it over that number..the valves will start to float and burn above that rpm).
Cheers,
Larry DeMers
s/v DeLaMer
Cape Dory 30
demers@sgi.com
This sounds like a governor problem. Sometimes these mechanical devices get crudded over and stick. Question: When the engine starts to change rpm on you, does it do so once and stay at the new rpm, or will it work up then work down the rpm scale? Does it randomly do this? Or is it repeatable at a specific rpm? Other possible causes would be the injector pumps metering section. If the metering mechanism is fouled, it will regulate fuel unevenly, resulting in the rpm wandering.
Does this happen at lower rpm at all? Do you use 2500 rpm much? (2600 rpm is the max rpm the MD7B is supposed to see, so I would not run it over that number..the valves will start to float and burn above that rpm).
Cheers,
Larry DeMers
s/v DeLaMer
Cape Dory 30
Boyd wrote: Yes there is a perceptable change in engine sound indicating that the rpm is really changing. The fan belt is tight. I will check the alternator connections tonight. I dont have access to a mechanical tach as of now.
Larry DeMers wrote: Sounds like the governor is not reacting right. Is there a correspnding engine sound change along with the tach. indication? That would eliminate just a tach problem then (otherwise, check for loose or dirty tach connections on engine).
Larry DeMers
s/v DeLaMer
CD 30
Boyd wrote: Hi Group...
I am out of ideas why my Westerbeke 21a on Tern will not hold a constant rpm at full throttle. The engine slowly occillates between 2500rpm and 3000rpm at full throttle (in gear going forward). Most of the time it holds between 2500 and 2600 and occasionally will speed up to 3000.
The prop is clean, the filters were changed 6 months ago with few hours on them. The bowl at the bottom of the Racor is clean with just a tiny amout of sediment. I am meticulous with BioBor and Diesel "start and stor". The tank was topped off in August with about 12 gallons. She starts well and doesnt smoke except for a little grey smoke at full throttle.
Does anyone have a suggestion what to check next?
Thanks Boyd
demers@sgi.com
-
D. Stump, Hanalei
Re: Hey, Larry???????
Captain Demers,
Since we are on diesel engines, I have a Universal 18, 14hp diesel on Hanalei. This past year the throttle started hanging up. I checked all cables and connections and all are freePedestal checks out OK too. It appears something is hanging up inside the throttle body(if that's what it's called). If I push on the bell crank on top of the shaft coming straight up out of the top of the engine, it will free up.
Any ideas as to what it could be? The yard guys looked at me like a "deer in the headlights" when I asked them about it....
Dave Stump
s/v Hanalei
Since we are on diesel engines, I have a Universal 18, 14hp diesel on Hanalei. This past year the throttle started hanging up. I checked all cables and connections and all are freePedestal checks out OK too. It appears something is hanging up inside the throttle body(if that's what it's called). If I push on the bell crank on top of the shaft coming straight up out of the top of the engine, it will free up.
Any ideas as to what it could be? The yard guys looked at me like a "deer in the headlights" when I asked them about it....
Dave Stump
s/v Hanalei
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Mark Yashinsky
How about me???
Is there slop in that shaft going into the pump body??? Could be wear in that top bushing and the shaft is getting cockeyed and jamming. Is the cable itself getting jammed when the throttle shaft moves up???
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Larry DeMers
Re: Hey, Larry???????
Cap't. Dave,
Nahh, ya went and spilled some sticky grog on the throttle last summer when that doxy you are associated with hickupped and stepped on your foot. Just wash it down with some club soda!
Heh..well, what I really would do first is to disconnect the cable from the bellcrank on the engine, then try it's freedom of movement, as Mark Y. was saying. Any wear will still be effecting the throttle inner core, but not as severly due to the load on the far end (engine) having been removed. If there is no trouble with the cable once disconnected, then you should go to the engine and see if that bellcrank moves smoothly and easily. You might try some LPS or similar spray *heavy* lubricant (not WD40 here..it'll dry out too quickly) on the throttle bellcrank and anything moving in that area.
I have noticed on my CD30, that the throttle is sticky too..after rebuilding the pedestal completely. I suspec that I rotated the inner core a bit, and it is out of the groove it forms when first installed. It needs to be looked at too. Did you disconnect the throttle lever from the cable at all? That is all I did and it now is sticky..needing a little more pressure to move, and infact the engines vibes cause it to change rpm settings after a while due to the vibes shaking it free from the hangup point. You can lubricate these cables with a teflon or dry lubricant, especially where they exit the throttle body itself..there is a little collet there that runs dry most of the time. I have actually pulled the wire inner core back a ways, and then sprayed dry lube down the tube until it came out the other end, but that is WAY too much, and it leaked all over creation, for the next 5 years. (different boat than present)..but it never stuck again.
Let us know what is found..I'll probably have the same thing to do in a few weeks.
Cheerio,
Larry DeMers
s/v DeLaMer
Cape Dory 30
demers@sgi.com
Nahh, ya went and spilled some sticky grog on the throttle last summer when that doxy you are associated with hickupped and stepped on your foot. Just wash it down with some club soda!
Heh..well, what I really would do first is to disconnect the cable from the bellcrank on the engine, then try it's freedom of movement, as Mark Y. was saying. Any wear will still be effecting the throttle inner core, but not as severly due to the load on the far end (engine) having been removed. If there is no trouble with the cable once disconnected, then you should go to the engine and see if that bellcrank moves smoothly and easily. You might try some LPS or similar spray *heavy* lubricant (not WD40 here..it'll dry out too quickly) on the throttle bellcrank and anything moving in that area.
I have noticed on my CD30, that the throttle is sticky too..after rebuilding the pedestal completely. I suspec that I rotated the inner core a bit, and it is out of the groove it forms when first installed. It needs to be looked at too. Did you disconnect the throttle lever from the cable at all? That is all I did and it now is sticky..needing a little more pressure to move, and infact the engines vibes cause it to change rpm settings after a while due to the vibes shaking it free from the hangup point. You can lubricate these cables with a teflon or dry lubricant, especially where they exit the throttle body itself..there is a little collet there that runs dry most of the time. I have actually pulled the wire inner core back a ways, and then sprayed dry lube down the tube until it came out the other end, but that is WAY too much, and it leaked all over creation, for the next 5 years. (different boat than present)..but it never stuck again.
Let us know what is found..I'll probably have the same thing to do in a few weeks.
Cheerio,
Larry DeMers
s/v DeLaMer
Cape Dory 30
D. Stump, Hanalei wrote: Captain Demers,
Since we are on diesel engines, I have a Universal 18, 14hp diesel on Hanalei. This past year the throttle started hanging up. I checked all cables and connections and all are freePedestal checks out OK too. It appears something is hanging up inside the throttle body(if that's what it's called). If I push on the bell crank on top of the shaft coming straight up out of the top of the engine, it will free up.
Any ideas as to what it could be? The yard guys looked at me like a "deer in the headlights" when I asked them about it....
Dave Stump
s/v Hanalei
demers@sgi.com
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Richard Feffer
Re: Speaking of throttle controls
Speaking of throttle controls: On my Westerbeke 21A, the trottle always seems to settle back to about 2200 rpm. There is no resistance when advancing the throttle to higher rpms. I'd like to keep the revs around 2500-2700, but as soon as I release the control, it settles back to around 2200. It would seem there may be some sort of a friction brake either on the cable or perhaps on the fuel pump. Anyone have any ideas?
Richard Feffer
s/v Adamarie
CD30MKII
RichFef@Prodigy.net
Richard Feffer
s/v Adamarie
CD30MKII
RichFef@Prodigy.net
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Boyd
I learned a lot ... important lesson.
When a problem arises it is my nature to think of what could be the most costly and complicated cause. After talking with my Westerbeke dealer and several other mechanical people and checking out what was on this board I decided to change the filters as a first step even though the filters were changed in August and only had about 10 hours on them. Thats why I didnt consider them as a source of the problem initially.
Changed them all last night and the engine now reaches its 3200 max rpm and the tach is stable at all rpm's. Partially clogged primary filter seems to be the cause. I think I have a bug problem in the tank even though the bowl of the Racor was virtually empty and the fuel clear. No black stuff anywhere inside the fuel system. The only particles in the Racor bowl were more like sawdust in color and size and darn few of them. I am going to install a vacuum gauge on the suction side of the Racor. Mechanic said that at negitive 5# the engine will shut down. But with a gauge you can see that event comming. If I had one then the problem would have been immediatly apparent. He said that not being able to make max rpm or "hunting" is sometimes the result of a partially plugged filer.
I am also going to have the tank pumped and filtered by one of those tank cleaners.
Each experience is a teacher and simple solutions are possible. Whew!
Thanks for all your suggestions... Boyd
P.S. Those cables tend to rust internally. I pour a little motor oil in from the top and work the cable to help exclude water. Any dip in the cable will hold water and rust the cable out from the inside. I replaced mine when I first got the boat.. it was rusted thru. Edson sells them.
Tern30@aol.com
Changed them all last night and the engine now reaches its 3200 max rpm and the tach is stable at all rpm's. Partially clogged primary filter seems to be the cause. I think I have a bug problem in the tank even though the bowl of the Racor was virtually empty and the fuel clear. No black stuff anywhere inside the fuel system. The only particles in the Racor bowl were more like sawdust in color and size and darn few of them. I am going to install a vacuum gauge on the suction side of the Racor. Mechanic said that at negitive 5# the engine will shut down. But with a gauge you can see that event comming. If I had one then the problem would have been immediatly apparent. He said that not being able to make max rpm or "hunting" is sometimes the result of a partially plugged filer.
I am also going to have the tank pumped and filtered by one of those tank cleaners.
Each experience is a teacher and simple solutions are possible. Whew!
Thanks for all your suggestions... Boyd
P.S. Those cables tend to rust internally. I pour a little motor oil in from the top and work the cable to help exclude water. Any dip in the cable will hold water and rust the cable out from the inside. I replaced mine when I first got the boat.. it was rusted thru. Edson sells them.
Tern30@aol.com
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Mark Yashinsky
Re: Speaking of throttle controls
Does the throttle itself move back and the RPM's fall off (everything is very well lubricated)??? There are friction devices that clamp to the wire cable itself and provide more drag. Dont know brand names, just seen them used and they can provide a tremendous about of drag (cant move the !@#$%^ thing). This was on a pedestal mount.
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Michael Heintz
Re: Speaking of throttle controls
Fef,
It's funny Macht Nichts does the exact same thing!!!!!! I've always figured that where she wants to be!!!!
Maybe we can get Cap. Larry to comment on this!!!
Michael Heintz
Captain Commanding
s/v Macht Nichts
CD 30 MK II
It's funny Macht Nichts does the exact same thing!!!!!! I've always figured that where she wants to be!!!!
Maybe we can get Cap. Larry to comment on this!!!
Michael Heintz
Captain Commanding
s/v Macht Nichts
CD 30 MK II
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Boyd
Re: Speaking of throttle controls
I had the same thing on Tern when I got her. I romoved the upper housing and compass from the edson pedistal steering. There is a friction ajusting nut on the shaft of the throttle. Tighten it up to the point it will hold max throttle.
Boyd
Tern30@aol.com
Boyd
Richard Feffer wrote: Speaking of throttle controls: On my Westerbeke 21A, the trottle always seems to settle back to about 2200 rpm. There is no resistance when advancing the throttle to higher rpms. I'd like to keep the revs around 2500-2700, but as soon as I release the control, it settles back to around 2200. It would seem there may be some sort of a friction brake either on the cable or perhaps on the fuel pump. Anyone have any ideas?
Richard Feffer
s/v Adamarie
CD30MKII
Tern30@aol.com
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Hanalei
Re: Larry and Mark......
Captains,
Respectfully Sirs, the answer is NO to both of your comments. The cable is very free, I did disconnect it. The throttle shaft is not loose. So, it really has me Stumped---pun intended. What is inside that throttle area on top of the engine? Larry, your suggestion of LPS might be the solution, I have lubed that area in the past and gotten relief for a short time using WD-40............your comments Sirs....
Hanalei
Respectfully Sirs, the answer is NO to both of your comments. The cable is very free, I did disconnect it. The throttle shaft is not loose. So, it really has me Stumped---pun intended. What is inside that throttle area on top of the engine? Larry, your suggestion of LPS might be the solution, I have lubed that area in the past and gotten relief for a short time using WD-40............your comments Sirs....
Hanalei