Another PA50 Idle Issue

I was given this PA a few months ago and it hadn’t been ran 10 or so years. There was fuel in the tank and of course smelled like a can of varnish. So after weeks of soaking and flushing, soaking and flushing, I got things pretty clean. Surprisingly, the inside of the carb wasn’t too bad. Took it apart as much as I could, used several cans of Berryman Chemtool and lots of compressed air. Put it all back together with new line, inline filter etc., and BAM, she started right up and ran pretty good.

Obviously not being a daily driver, it sat for several weeks. When I went to start it up last week, it wouldn’t idle at all. Runs great at anything over about to 1/3 throttle, but no idle. After spending a good amount of time reading other threads on this forum, I got more confused than anything so I went back to my good ‘ol’ common sense of mentality and experience beings how I’ve been tinkering and fixing these things since the late 60’s(yeah I’m old).

Ok, so I can start the bike and keep it running by just using the choke lever. When it starts to die, I put the choke on full and will stay running. I the open the choke, it revs really high, then wants to die again. Continuing to do this keeps it running.

My conclusion? Idle circuit. So off comes the carb and thanks to some great posts on the other threads, I found the tiny tiny little orifice under the screw below the throttle stop screw. I think it is(or was) plugged. More to come….

Re: Another PA50 Idle Issue

So last night I soaked the carb in parts dip for a couple hours, cleaned it real good in hot soapy water the sprayed it with WD for the night. This morning I went to tackle that idle circuit orifice hole. WOW is that hole small. I ended up using the tip of the smallest needle I could find then progressed from there. The tip on the other thread to use the smallest end of a guitar string is a good one. It’s rigid and works well but you may have to start with a needle like I did.

I’m almost certain the hole is clear now because if I blow compressed air down the hole where the orifice is, close the idle circuit needle and hold my finger over hole behind the choke plate, I can feel a tiny bit of air coming out the bottom of the main jet tube. And I couldn’t before. Got some new rubber seals coming from Treatland(are they any good) then I’ll post back here.

Re: Another PA50 Idle Issue

Sounds like you got it, those carbs have to be super clean to work right, while you have things apart clean out the little screen filter in the petcock.

Re: Another PA50 Idle Issue

For tiny holes like the carb has a single strand of brake cable works great.

Re: Another PA50 Idle Issue

I’ve got a set of torch tip cleaners and even the smallest one was still too big. Waiting on the little black diverter seal for the petcock, which by the way I had a tough time finding. I found this on ebay, hoping it will fit.

OMG Made in Italy petcock replacement rubber seal 14mm diameter 0220132264 NBR-H

Anyone ever try flattening the float bowl? Mine is a little warped on the ends. I might try doing it in a vice but I sure don’t want to break it.

Re: Another PA50 Idle Issue

> Chris Lay wrote:

> -------------------------------------------------------

> I’ve got a set of torch tip cleaners and even the smallest one was still

> too big. Waiting on the little black diverter seal for the petcock,

> which by the way I had a tough time finding. I found this on ebay,

> hoping it will fit.

>

> OMG Made in Italy petcock replacement rubber seal 14mm diameter

> 0220132264 NBR-H

>

> Anyone ever try flattening the float bowl? Mine is a little warped on

> the ends. I might try doing it in a vice but I sure don’t want to break

> it.

Lay a square of sand paper on a flat surface . Tape it down . Figure 8 the bowl until flat . ;)

Re: Another PA50 Idle Issue

I ended up soaking the bowl in mega hot water for a few minutes then put the bowl screws in backwards, put it in my vice and slowly tightened it pushing on the screws and the very bottom of the bowl. Worked like a charm.

Re: Another PA50 Idle Issue

Ok, the end of the story. It was indeed the idle circuit hole.

At first though, it would pop an pop and try to run but nothing over that. So I pulled the carb off again, checked everything, scratched my head, put it on. Same thing. Screw it I said. Slammed down my Mikes Harder Mango(or 3) and went to bed.

Today a new day. Same damn thing. No amount of throttle would make a difference. Oh wait……..throttle? As in throttle cable? Um…duh…I forgot to hook up the throttle cable! DOH! What an idiot!

She purring like a kitten now. Thanks for the comments guys!

Chris

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