81' 7.5 hp

[quackaddict1]

Hey guys, A friend of mine recently acquired the above mentioned motor, the motor runs strong, but idles very very low and cuts out frequently at this low idle. I would like to increase the idle but I am unfamiliar with this motor, there is no adjustment except for a knob on the handle,you can turn the knob and it doesn't act any differently at any setting. Dose the knob just restrict how far the throttle can move? Is there an adjustment on the carb?

It is also noteworthy that the motor will shift in and out of gears and idle all day long with the throttle increased slightly.

 

[wbeaton]

Re: 81' 7.5 hp

I'm not familiar with that motor, but there should be an idle stop that you can adjust. Take a look at the throttle linkage with the cowl off. Turn the throttle on and off until you see where it physically contacts some sort of adjustable stop. Then move that stopper out a little. It may just be a screw located where the tiller arm gears contact the throttle gear at the motor end of the tiller arm.

 

[Vic.S]

Re: 81' 7.5 hp

The knob on the tiller end is the idle speed adjustment. If you turn it anticlockwise you should then be able to turn the twist grip further (clockwise) to reduce the idle speed.

here is a diagram of the carb

#15 is the idle mixture adjustment. See HERE for instructions on adjusting the mixture.

The screw #2 should be used to set the roller #1 so that it only just contacts the cam plate against which it runs when aligned with the reference mark on the cam. But avoid touching it unless you are sure it needs adjusting.

If the cam cannot be positioned to bring the mark in line with the roller within the range of the tiller end knob adjustment then the threaded "P" clip on the throttle cable outer may need to be repositioned. # 33 in THIS DIAGRAM


If the ignition timing has been tampered with then I am afraid I cannot help. You will have to consult a manual or a higher authority.


Thes pictures might help, click to view

 

[quackaddict1]

Re: 81' 7.5 hp

Thanks for the reply Vic, I thought that plastic deal was the cam adjustment, this particular motor has its backed all the way out. I will check it for alignment. If that isn't it, I suspect the may be some crud in the idle circut.