Talk Morgan Forums Morgan Sports Cars Morgan Three Wheeler & Super 3 Revs not going to idle

Hello fellow three wheelers,

I am noticing a reluctance for engine to reduce to idle. When changing gear it does not reduce revs despite throttle being lifted off. Stranger still I stopped after a run and was still at 3000 revs.

Only done 400 miles and I remember early cars had throttle cable with a big bend above engine but maybe the cowl for fan modification causes a poor route?

Cable routing, unless done with insufficient radii, is unlikely to be the culprit, as if done wrong it would have been apparent from day 1.

Don't discount a sticking throttle pedal. The non sealed footwells and under dash area of the M3W allow all sorts of dust and debris into the pedal area.

After a newly developed issue this spring with a slightly high (1200-1400rpm) idle, a bit of sleuthing revealed the throttle cable had zero slack at the throttle body (there should be just a small but discernible amount) and traced the issue back to a sticking pedal. A bit of spray oil at the pedal pivot later, the pedal was freed off and normal idle returned.

One of my many winter projects this year will be to remove and clean/plate/repaint the pedal assembly and see if I can't come up with simple mods to facilitate periodic lubrication of the pedal pivots without standing on ones head.

If the throttle cable seems to be working correctly the problem could be with the Idle Air Control. It sits on the top of the throttle body with a plug going to it. They can be cleaned but that is unlikely to be the problem with your almost new car and it will be a back to the dealer job for warranty work I expect.

I agree with above. Start by cleaning the idle air control valve and the passage in the throtle body it sits in. I use q-tips to clean this so I don't spray crap down the i take into the engine.

I also have this problem on occasion. Except with my car the idle is a bit higher than normal and rougher and occurs both at the stoplight or when shifting gears. A blip of the throttle usually works to calm it down at the stoplight.

So it sounds like I need to check the throttle cable slack, gas pedal pivot point, and clean or replace the idle air control valve.

Many thanks for input. Pedal seems to move smoothly. Cleaned sensor. Not much slack in cable. Still the same. Frustrated

Mine had similar symptoms - turned out to be a frayed throttle cable at the throttle body end causing the throttle to stick open slightly.

If it is this and it gets worse then eventually the throttle will stick open and once you switch the engine off and try to restart it the fuel pump will run, the engine will turn over but it won't fire up.

Two more ideas:

verify the cable is properly routed at the throttle body. If the throttle is opened manually for a cleaning or inspection, the cable can come out of the groove in the 'disc' on the side of the throttle body.

when the high idle situation occurs, shut off the machine and without touching the throttle, remove the air cleaner to inspect the position of the throttle plate (which should be totally closed).

I thought it was throttle cable but dealer found sticky butterfly valve . Replacement cable still not arrived from MMC!

G56 wings arrived today!!!

Sticky throttle body probably from oil/gunk being pumped into the throttle body from the cam chest vent tube.