Throttle Creep

[Jaysay]

I have a Morse MV2 combined throttle/gearchange control. For some reason, after 2000 engine hours and five years' boat use, the throttle has taken to slipping back to idle from all engine speeds below about 1700 rpm. Can anyone suggest a modification or adjustment to prevent this happening (my knee gets a little tired holding open the throttle after a while!). Clearly, some form of extra friction is in order and I have a few ideas to try, but perhaps someone has been here before?

[Tony Brooks]

I have a Morse MV2 combined throttle/gearchange control. For some reason, after 2000 engine hours and five years' boat use, the throttle has taken to slipping back to idle from all engine speeds below about 1700 rpm. Can anyone suggest a modification or adjustment to prevent this happening (my knee gets a little tired holding open the throttle after a while!). Clearly, some form of extra friction is in order and I have a few ideas to try, but perhaps someone has been here before?

 

 

Yes - if this is the vertical surface mount one with the chrome metal lever and pull out knob. There was as a thread on this a while ago.

 

I have been talking to Morse about this and all they say is to fit a "pull open" spring to the throttle lever on the engine to counter the closing forces when the engine is running.

 

I am not so sure about that and it may mean making and finding a fitting point for a bracket.

 

My injector pump had a fairly strong return spring on it and removing it solved my problem. Such a spring is not normally required because our cables push as well as pull - unlike most vehicles. I do not think this will work on the Jap made base engines though.

 

If that had not worked I think I would have got hold of a length of strong steel strip, angle or U section, two jubilee clips and a large nut or block of metal. Thread the jubilee clips over the cable and slide the strip into them. Position the clips at (say) 1/4 way in from either end. Place the large nut or block in the centre of the metal between the metal and the cable. Gradually tighten the clips to force the cable into a U. Keep checking the cable so you only put enough friction into it to stop the creep and not enough to make it stiff. I have no idea if this will work in practise, but it must be worth a try.

[Noah]

Hi Tony

 

I’m going to that a try on mine. I fitted a new Morse-type lever and have the same problem with the strong “throttle” spring on my Kubota engine. There is a friction screw in the Morse lever but even when fully tight it does not prevent slipping back at anything over quarter throttle. When I’m pushing a tide and need full power I hang a weight (pair of binoculars/pint glass) over the lever to keep it in place!

 

Noah

[Machpoint005]

When I’m pushing a tide and need full power I hang a weight (...pint glass) over the lever to keep it in place!

 

Noah

Presumably the spilt beer increases the coefficient of friction and stops the Morse handle slipping back?

 

Ian

[Jaysay]

Thanks Tony - I think I'll try that.

 

My boat builder did introduce the 'spring hold-open' option as a MOD some time ago (before I had the problem), but I took it off because it resulted in the engine idling at about 1200 rpm. It made manoeuving and coming into locks a whole new experience. Besides, I question an engineering solution that has a failure mode which results in a throttle being pulled open.

[carlt]

I thought this was a thread started by a spiritualist, about what they'd like to do to me!

 

I'll get me coat.

[Speedwell]

I altered the position of the throttle close spring to reduce the tension but this proved insufficient. A loop of suitable thickness cord round the throttle lever to increase friction between the lever and the base finally did the trick.

Arthur