Dave's 1650 Project

[CHWNY]

Originally Posted by CC1650Dave

Yeah, the first time was rough as well. I did let it warm up, and it started easier after that, but still not great.





Which fasteners are you talking about re-torquing? Head bolts?

I'll go clean the points and check the plug.

What's a welch plug? Not something I recall reading about...

I'll check out the carb some more as well. I did a half-hour dip on it when I cleaned it, but I'm not sure I ever completely inspected all of the holes to assure they were completely clean.

Thanks for the tips!

Hey How do you just quote part of a post?

Yea, re-torque all fasteners, mainly head bolts. After running every thing that's bolted on will settle in and should be checked for tightness, Particularly if your having problems (measure twice N cut once, so to speak)

Welch plugs are caps required to cover passages machined/cast into the carb. body.they are swagged into place to make a seal. When you rebuild a carb that has sat for a long time or was full of fine sediment, the internal passages can get clogged and dipping just can't get in there and the plugs need to be removed passages cleared and plugs re-installed CAREFULLY. I have quite a few where the welch plugs were rusted through, mostly on snowblowers. If these passages have crud in them or are not sealed good the adjustments won't have much of an effect. Unfortunately these days most rebuild kits don't include these items anymore and they cost twice as much!

Try closing the preliminary settings up a bit. I use 1 1/4 low speed and 1 1/2-1 3/4 high speed on all motors as a starting point. You can always choke it a little, if too lean to start.

[CC1650Dave]

Originally Posted by Matt G.

the fact that you can turn the needles quite a ways in either direction with minimal effect suggests something may be blocked in the carb and it might instead be too lean instead of too rich. It should be pretty responsive to mixture changes.

I'm starting to think this may be the case as well. I went back to the settings you gave, and to start it while still warm requires a little bit of choke.

I couldn't get it to idle well enough to bring it down to low throttle and try shooting it back up. So I tried moving the low speed screw to get a better idle, and I went a turn one way or the other without any real effect.

Take the dang carb off and clean it again? Now I remember how much I always hated carb issues when I was a kid working on mini-bikes...

[CC1650Dave]

Originally Posted by CHWNY

Hey How do you just quote part of a post?

You can wrap any segment in quote tags (QUOTE) and (/QUOTE) (use brackets [] instead of parentheses.) Or highlight a segment and click on the "Wrap [Quote] tags around selected text" button in the advanced editor.



I can only find one thing on the outside of the carb that looks like it could be a plug. I read more about them and it looks like an hex-keyed plug is used somewhere. I see something foil-like on a round spot that must be the seal over that plug (?)

[Matt G.]

Check all of the little holes in the main needle first...you should be able to stick the pointy end in your mouth and blow through it, making air come out the set of holes on the top. If you can't easily blow through it, it's clogged.

[CC1650Dave]

It was a brand new main needle, but I'll check it. The original one, when I took the carb apart for cleaning, had a small shard of metal coming off the tip. It's like it had sealed itself to the carb after sitting so long, and when I removed it the metal kind of gave.

I think I remember seeing the shard and knocking it off with my finger, so it wouldn't be in the carb - but it's possible there could be a little material that stayed in there through cleaning.

[CHWNY]

Dave, There will be plug(s) under the bowl as well. Actually above the bowl. If you do remove them you could deposit something like nail polish (don't tell the wife) to ensure the seal. please read up on the procedure as you can RUIN an expensive, sometimes Irreplaceable carb. Thanks for the Quote tip. P.S. There are passages plugged with SS balls as well I would NOT remove them, Just the tin ones!!!

[Matt G.]

I'm not sure it's necessary to remove any of those plugs...I've rebuilt many carbs, a lot of which were really nasty, and they all worked after a good soaking in carb cleaner. If it is left in there for a couple hours (more if it's cold out) that is generally enough to clean it inside and out.

A couple more ideas; is the bowl vent clear, and do you have good fuel flow to the carb? Another thing I do when I'm trying to determine if I have an ignition or fuel problem and can't tell is to squirt some gas directly into the intake beyond the carb (with a little 2-cycle oil mixed in so you're less likely to have the oil washed off of the rings) and then try to start it. If it still doesn't want to start (you still might have to pull the choke) then you should be looking for an ignition problem instead.

[CC1650Dave]

Here's some info that may help you guys identify the problem:

Right now, with the high idle @ 2.25 turns and the idle @ 1.75, the engine will start (semi-warm) with the throttle at about half, and the choke anywhere from half to full. Let the choke off immediately and it will run.

It runs decent at mid to high speed, but really once you drop the throttle below half it starts to run real slow and wants to die. The idle speed set screw would have to be all the way in to even touch the throttle arm (or whatever you call the metal piece that taps the screw) when the engine is idling. That can't be right, eh?

[CC1650Dave]

Originally Posted by Matt G.

is the bowl vent clear, and do you have good fuel flow to the carb?

Is this the bowl vent? If so, it looks fine.

Another thing I do when I'm trying to determine if I have an ignition or fuel problem and can't tell is to squirt some gas directly into the intake beyond the carb (with a little 2-cycle oil mixed in so you're less likely to have the oil washed off of the rings) and then try to start it. If it still doesn't want to start (you still might have to pull the choke) then you should be looking for an ignition problem instead.

I want to shelf this one for a bit if you don't mind. It's not like it won't start (at least warm) it's just that it doesn't seem to start right.

[Sugarmaker]

Dave,
I am having similar problems right now in most of the same areas.
Now is where my patience factor needs to really kick in. When we are this close we want everything to work!
Regards,
Chris