I had a 1980 Hunter 30 with a dealer upgraded 2QM15. There was no engine shut-off cable and the throttle was used to stop the engine.
Diesel shutoff question
- Thread starter Wm. Gill
- Start date
2QM15 has a throttle linkage that accepts a stop cable. I think that Hunter did not supply the stop cable but it could be installed. My 1980 H33 did not have a stop cable when I bought it used in 2002 but the throttle linkage was designed for a stop cable. Easy and necessary upgrade.
Ok, now I am confused. Does that cable then shut off the fuel supply, or the intake air?
Its been awhile since I have even seen the engine compartment in my boat. I have two shutoff “T” handles. The one I use most is in the instrument panel, and the second is in the quarter berth and connected to the fuel tank. The instrument handle shuts down the engine almost immediately. (Yanmar 2GM20F).
Now that is an odd one. Any idea what the cable is connected to at the fuel tank ? ? ?
If it's connected to a fuel shut off valve, I can't think of worse idea except maybe building the Fukushima nuclear plant on the edge of the ocean
! ! ! When and if the valve is closed (supposedly to shut down the engine or ? ? ? ?) the injector pump will pull a near perfect vacuum which will be looking for the tiniest leak to admit air. Will also try to collapse the fuel hose. Any way you look at it, just not a good idea.
Ok I finally pulled the frozen cable clearly marked "Engine Stop" but it didn't connect to the engine stop remote control, it connected to the decompression remote control. There is nothing connected to the engine stop remote control. I got the definite impression here that the decompression control shouldn't be used to stop the engine.
So for you Yanmar 2QM15 folks I have a couple new questions. I still don't want the throttle to stall the engine, it's too difficult to restart while trying to maintain control of a suddenly ballistic boat, especially in close spaces like a marina. Question 1: Is using the decompression remote a no no for deliberately stopping an idling engine, because I am going to replace the cable with a good one either way. Or should I retrofit the engine with an actual engine stop remote control (assuming I can find a good place to put the new knob)?
Question 2. Looking at the engine stop remote control it looks like it won't actually stop the engine, but at best inhibit or allow the range of motion of the regulator lever allowing the throttle to stop the engine. Though the mechanics of it suggests it really won't inhibit regulator movement by the throttle anyway. Am I missing something? If I'm not wouldn't retrofitting to include an engine stop remote control knob be a waste of time?
EDIT: A little digging suggests using decompression to stop the engine is bad for the valves, so there's that.
So for you Yanmar 2QM15 folks I have a couple new questions. I still don't want the throttle to stall the engine, it's too difficult to restart while trying to maintain control of a suddenly ballistic boat, especially in close spaces like a marina. Question 1: Is using the decompression remote a no no for deliberately stopping an idling engine, because I am going to replace the cable with a good one either way. Or should I retrofit the engine with an actual engine stop remote control (assuming I can find a good place to put the new knob)?
Question 2. Looking at the engine stop remote control it looks like it won't actually stop the engine, but at best inhibit or allow the range of motion of the regulator lever allowing the throttle to stop the engine. Though the mechanics of it suggests it really won't inhibit regulator movement by the throttle anyway. Am I missing something? If I'm not wouldn't retrofitting to include an engine stop remote control knob be a waste of time?
EDIT: A little digging suggests using decompression to stop the engine is bad for the valves, so there's that.
The problem with plane ownership is you can’t (legally) just go putzing around on it replacing this, installing that unless it is experimental. You have to be a certified airframe mechanic or a apprentice. It would drive me crazy not being able to dig into something that I owned.
The engine stop cable on your engine allows the regulator lever to rotate past the idle position and stops the engine independently of your throttle control. A small spring (called return spring) connected to the regulator lever actually moves the regulator beyond idle to stop. Adjusted properly your engine throttle control will allow your engine to operate from idle to full speed, a range of 800 to 3,250 RPM. It will not stop the engine as it is adjusted to only operate between 800 and 3,250 RPM. To stop your engine, move your throttle control to idle position (800 RPM) and then pull the stop cable to allow the return spring to move the regulator lever further and the stop the engine. This last pull on your stop cable does not require you to move the throttle control.
Love the explanation! I just recently removed and re-installed my timing gear case and in the process, replaced the regulator lever and idle adjuster. It was nice to visually observe exactly as you describe!
Without re-reading all the responses in this posting I might have missed something, but if the shutoff cable is NOT hooked up to the fuel shutoff why don't you just connect it there?
Thank you. When looking at the diagram of the engine stop, regulator lever, and return spring I thought that was the intended design. However, physical examination suggests that the return spring has to move both the regulator lever and pull the throttle cable connected to the other end of the lever which would otherwise oppose the lever action. The return spring seems to lack sufficient strength to do that, and additionally the spring loaded pin in the stop assembly does not seem to actually stop lever pivot even when not retracted by a stop cable. So hearing you concisely restate my original understanding of how it should work and confirming it actually does work, is what I needed to hear.
I will connect a cable to the stop pin as needed, and try to make the adjustments accordingly, because frankly right now with no cable attached to the stop pin, the throttle seems uninhibited by the stop pin (which is why it now can kill the engine), and the stop pin adjustment seems to already be at its limits. I didn't want to spend a lot of time on something that wasn't going to work anyway, so thank you for your confirmation of the design, and I will continue to work on the application (the difference between a design on paper, and its implementation in the real world).
On further examination it looks like if I pivot the stop pin assembly bracket a few degrees CCW it will increase tension on the return spring, AND change the contact angle between the regulator lever and the stop pin so that it presses the pin sideways (no motion) instead of depressing it like a spring loaded button (as it seems to be doing now).
[This will help those of you without the images see what we are talking about]
Now the remaining question is should I install a new cable to the decompression lever?
The cable is completely frozen and needs to be replaced. What surprised me was it was connected to the decompression lever, not the engine stop pin.
You will probably never need the decompression control cable. For now, just ignore it.
The return spring does not have to pull the throttle cable. What the drawing does not show is that the throttle control cable end has a slot that allows the regulator to move beyond idle to stop. Regarding the return spring: that spring is no longer available from Yanmar. No matter, you can find a suitable spring elsewhere. It need not be a robust spring as very little force is needed to pull the regulator past idle to stop after you have compressed the stop spring with your stop cable. The throttle control cable end should be adjusted so that there is free movement of the regulator arm at idle within the cable end slot. I do not think you should have to rotate the bracket from the factory position unless it has been moved to an odd spot. Once you get this right you will never have to look at it again and you will never stall while moving about the marina.
The return spring does not have to pull the throttle cable. What the drawing does not show is that the throttle control cable end has a slot that allows the regulator to move beyond idle to stop. Regarding the return spring: that spring is no longer available from Yanmar. No matter, you can find a suitable spring elsewhere. It need not be a robust spring as very little force is needed to pull the regulator past idle to stop after you have compressed the stop spring with your stop cable. The throttle control cable end should be adjusted so that there is free movement of the regulator arm at idle within the cable end slot. I do not think you should have to rotate the bracket from the factory position unless it has been moved to an odd spot. Once you get this right you will never have to look at it again and you will never stall while moving about the marina.
What you describe does not seem to comport with what I observed. However when examining the push/pull of the throttle cable I was unaware of the "slot" action you describe, so the severe maladjustment of the cable may be what's overriding the intended operation. Assuming that slot, adjusting the throttle cable so that when the throttle lever is at its physical limit the push of the cable stops at idle. In which case the spring and pin on the stop assembly need only be strong enough to overcome the pull of the return spring until the stop pin is retracted. All of which says messing with the bracket is ill-advised. Observing that the slot action (allowable motion of the regulator lever without corresponding cable movement) is uninhibited (not stuck) is easy enough to check.
For those whose eyes have glazed over, what Roy is saying is when the throttle cable pushes the regulator lever as far as the cable is physically able, the return spring can then pull it an additional couple degrees, but the spring on the stop pin pushes the lever in the opposite direction, and being stronger wins that tug of war. When the stop cable is pulled the pin is retracted so the return spring can now pull the lever that last few degrees. It's not working now because a maladjusted throttle cable is allowed to push the lever too far.
I am ordering a replacement cable today, and will report back shortly.
Thanks Roy, and thanks for the advice on the decompression cable.
Special ordered cable came. It wasn't correct because though the knob end was acceptable, the engine end was bare cable and conduit ( the stationary housing, inside of which the cable moves). It did not have a threaded, adjustable terminator on the engine end of the conduit. However, close examination shows it would not have worked even if it did fit correctly.
The clevis is not slotted, thus movement of the throttle lever and the governor lever are fixed in relation to each other i.e. neither lever can move without corresponding movement of the other. This means the governor lever cannot move beyond what the throttle cable has already pushed it.
The return spring is not strong enough to pull both the control lever and the attached cable. Additionally the stop spring will not stop too much cable push.
Being as there is no slot action, there is no point in finding the "correct" cable. I could try to find another clevis with slotted pivot holes, then find a cable with both ends properly terminated, but I think I will just haywire a mechanical stop at the throttle lever that can be easily moved to allow the additional lever movement needed to stop the engine.
The clevis is not slotted, thus movement of the throttle lever and the governor lever are fixed in relation to each other i.e. neither lever can move without corresponding movement of the other. This means the governor lever cannot move beyond what the throttle cable has already pushed it.
The return spring is not strong enough to pull both the control lever and the attached cable. Additionally the stop spring will not stop too much cable push.
Being as there is no slot action, there is no point in finding the "correct" cable. I could try to find another clevis with slotted pivot holes, then find a cable with both ends properly terminated, but I think I will just haywire a mechanical stop at the throttle lever that can be easily moved to allow the additional lever movement needed to stop the engine.
I do not have a close up photo of the slotted connection to the regulator lever on my engine handy. However, I found a drawing in the engine manual where it is shown clearly and I took a photo of that for you. It is on page 4-7 in the 2qm15 maintenance manual. See below
Your manual clearly shows a slotted clevis. Mine is not. I considered looking for a slotted clevis to retrofit the throttle, but then I still need to find an appropriately terminated shutoff cable, as the "universal" cable is worthless. I will come up with a temporary fix while I pursue the clevis and cable. This boat is a restoration project as well as a great sailboat, so if I can find the correct solution that's what I want, but I need an interim solution, so a kludge may be in order for the time being. Additionally the stop pin does not seem to be properly aligned with the regulator lever, so some brute force adjustment may be necessary also.
Looks like I will need to find a Yanmar parts supplier and not rely on other sources.
Thanks for the P/N, it's a start. Hopefully I will find the correct shutoff cable, and not have to resort to a custom fabrication.
This does not look to me like a fuel system that uses a separate engine shut down cable. It looks like it is a single control setup. The idle is set by the stop spring mechanism so that when the fuel control lever is brought to idle the regulator lever makes contact with the stop spring mechanism at the specified engine idle speed. There is usually a detent in the system at the fuel control lever. In order to shut the engine down it is necessary to push the fuel control lever physically past the detent into the shut down area. The slot on the clevis allows physical movement beyond the detent before it forces the regulator lever to compress the stop spring mechanism thus shutting the engine down. The return spring is only to keep the fuel control lever at the correct end of the clevis slot.
A dual control system, fuel control cable and engine shut down cable, usually will have a split fuel control lever with a rotary type of spring. It will also have a location to connect the fuel shut down cable.
The decompression levers are usually only deployed when hand cranking the engine to start it. It is possible that the shut down cable was added by someone who may not have understood how the system is supposed to work.
A dual control system, fuel control cable and engine shut down cable, usually will have a split fuel control lever with a rotary type of spring. It will also have a location to connect the fuel shut down cable.
The decompression levers are usually only deployed when hand cranking the engine to start it. It is possible that the shut down cable was added by someone who may not have understood how the system is supposed to work.
Well, some of what you say makes sense, some doesn't fit. I cannot feel any detent position on the throttle lever. It is possible the detent is worn beyond usefulness. The regulator lever has a bracket for a kill cable, but there wasn't any cable connected. The "universal" cable won't connect to this bracket. That the clevis is not slotted confirms that C&C modified this, probably to create a single cable operation, but the stop pin, and lack of detent make maneuvering in close spaces like a marina much too exciting after accidental stalls. Granted I am used to steering with the engines, but this boat doesn't have 2 Chrysler 360's, and only 1 screw, so that's out of the question.