Jiffy Model 30, Another question!

[Malmo]

I've got a Model 30 approx. 15 years old. The motor always starts and runs fine, except when it occasionally sticks at full throttle. The throttle lever itself doesn't stick and returns to the idle position when you release it, but the motor continues to run wide open. If you shut it off and restart it usually returns to an idle (but not always). Seems to happen more often when it's very cold. It's been doing this for a couple of years and I've run Seam Foam in the gas, but hasn't stopped the problem. Appears to be sticking internally so I suppose it's a cleaning issue?, but I'm not sure what I should do.

Any suggestions would be appreciated.

[Backwater Eddy]

This is hard deal to explain, but I will try. I had it happen to me on a older Jiffy years ago.

Fallow the linkage up under the recoil housing to where it links to a high speed advance. This is a separate throttle linkage that engages when it is in full throttle mode. Your linkage may be bent or possibly the screw that adjusts this high speed advance has fallen out or moved.

The screw may have backed out over time allowing the flipper to stay wide open when the air flow from the recoil hits it, even when you release the main throttle.

Hard to explain but look up under the shroud and you will see what I mean I think?

If that linkage binds up it will hold open on a full throttle.

Sorry I was not clearer.



~ ~ ~><sUMo> ~ ><>

Backwater Eddy ~ ~ ~><sUMo> ~ ><>

[Andy K]

Is it possible for this to do the opposite, and stick closed? Causing the motor to run rich all of the time?

Andy K.

[Pitts]

Iv'e never seen it but what BE describes seems like an air vane govenor that is on most smal engines. The linkage for the seperate throttle control (govenor) is brought back to the non throttle position by a spring make sure that spring is secured in a normal place and not getting hung up. Spray a carb cleaner on the outside of of the carb then use a dry spray lubricant to get everything working again.
Sometimes it can be as easy as the excess cable for the throttle has curled around and is hooking something when opened up and does not return to the normal min throttle position.
Should be fairly easy to fix.

Hope this helps.


Pitts

[Backwater Eddy]

Yah hay, thats the whats it thingy Eh!

:)

When it happened to me it would stick open as you drilled and held the throtle wide open. If thats the problem it is a easy fix.

Backwater Eddy ~ ~ ~><sUMo> ~ ><>

[Andy K]

I just bought a used Jiffy and used it for the first time this last weekend. It does seem to bogg down a little, and used a heck of a lot of gas (5 holes used the entire tank!). As it ran out of gas, (leaned out), the rpm increased and the thing took off and dug like crazy. Seems to me it's getting too much gas. Any ideas?

Andy K/CO

[KP]

Sounds like a fuel pump problem. Easy to fix on Walbro Carborators. Might as well rebuild the entire carb with the available carb kit.

[LukeS]

Carb should be fine. Same thin happened with mine. The first replie should fix all your problems if you understand what he means.

[Andy K]

Fuel pump? Where is it located?

[Andy K]

Bump to top

[KP]

It's actually a fuel pump diaphram on the fuel intake side of the carb. The diaphrams get old and sometimes split causing a huge use of fuel. The motor will still run but sluggish. As it runs out of fuel, the reduced flow causes a leaner condition making the motor run the way it should until it's finally our of fuel.

Other times, a cold motor will run better because the diaphram is stiff. As soon as the motor warms, the diaphram loosens up and the motor will run poorer from too much fuel flowing.