HS40 Won't start but has lots of spark

[RT MAN]

Same old story picked R2 I can pull on the starter until well I can't pull anymore.

It pops, It fires but it won't start. I installed an original rebuilt tecumseh carb I've given it a shots of quick start and it tries but still nothing but blisters and a soaking wet shirt.

1.5 Main
1 low idle
turned up idle set screw

Seems to have lots of compression as well.

I even changed to carb to and older tecumseh adjustable carb.

The carb that was on it was`a Lauson Power Products it is adjustable but has no bowl like the tecumseh just diaphram on the bottom.

Lot of popping firing and sputering but no start

There is fuel in the bowl that much I do know

I might add that this doesn't have the slanted intake and the carb is tilted. I dont know this will affect the ability to run or not.

 

[JustEnough]

Sounds like the flywheel key is sheared throwing the timing off.

 

[RT MAN]

JustEnough I haven't checked the key but I will,

just thought the intake not being slanted it might affect the float, but with the other diaphram style carb I thouht it should run regardless.

 

[Ruppster81]

Even without the slanted intake it should at least start and run. I've seen alot of people run their rupps this way but the diaphram carb would be best if you don't have the slant intake. I agree as stated above check the timing key. If thats good check the cam timing as well.

 

[marksteinhilber]

vacuum leak on intake or carb

If the flywheel key checks out and the timing or points hasn't been disturbed, then it would be an air or fuel problem. Engine should at least start briefly with starting fluid shot into carburator with air cleaner removed.

If there are leaks on your intake manifold gaskets, or around the carb throttle shaft, or even an air leak at one of the welch plugs in the carb, you won't get full ariflow past your venturi jets and fuel won't be drawn into the engine.

There is a trick using an unlit propane torch putting propane gas near the possible leaks. If this is done while the engine is being turned over, it may start to run or at least kick over like there is more fuel available.
Nail polish can be used to seal leaks in welch plugs and at flanged conections, but you should use new gaskets if this is the problem for a long term solution.

 

[oldsledz]

You could always put the front wheel up on a block so that the carb is level to test it.
But I don't think that is the problem.

 

[RT MAN]

Well I change the gas just to see if that would help, it did run for about 30 seconds first time ever it didn't knock or anything sounded fine but stalled hasn't restarted again though.

 

[RT MAN]

Well I checked the key it was noodled so I will install a new key. I'm not sure what the point should be set at they currently at 24 I have clean them although everything was spotless behinf the flywheel.

Point gap ?

 

[cncsparky]

Points at .020 and plug (CJ8) at .030 .

 

[RT MAN]

Well I got it running but I had to stop and take a break the fumes got to be to much.

It will run but very poorly, the low speed setting screws has no effect when I adjust it in or out I started at 1 full turn out. and 1.5 on the big one. so most of my initial problem was the ket and point being at 24 now for proper carb adjustment when I give it gas it doesn't rev but it helps it to stay running that all. a few time I let off on the throttle and it reved higher and smoothed out and then stalled. something must be plugged.

I'm thinking of installing the original diaphram carb back on it.

 

[RT MAN]

Well I have it starting every time now, but with the bowl carb is will only run with the choke on but I can't throttle it up at all or it stall if I open the choke it runs up smoothly for about 5 seconds and stalls.

I tried adjusting the high and then low idle but no cigar.

So I put the old carb back on and fires finebut doesn't but only ran for 1 second and dies.

This is a frustrating process. I sealed the intake manifold to the cylinder and a new gasket on the carb

 

[RT MAN]

Well I fianlly found the two little holes in the side of the carb that are closest to the intake side. They sare so small that, I looked athat carb at leat 20 times before I saw them, shows how badly I need glasses.