HS50 flames out exhaust

Birdball

Birdball

Member
#1
#1
Hi guys- new to the forum and really appreciate all of the deep knowledge here! I am messing around with an HS50 that i am prepping for a Ruttman Spyder. I removed the governor and installed a Dosens 631918 carb that I learned about from some other threads.

Engine starts fine and I got the idle smoothness optimized with the screw about 1.25 turns out (more than I expected). Then I revved it up to adjust the main jet. It is happiest at about 1.75 turns out, but it heats the exhaust cherry red and shoots a nice blue flame while revving. If I turn the key even a 1/4 turn in either direction is drops the rpm significantly.

So far I have checked and re-gapped the solid state to flywheel magnets to .0125 as specified and gapped the plug correctly. Both intake and exhaust lash is on the high end at .11 (.06 nominal spec). No cracks in the head, and new gaskets on the intake and exhaust so no air leaks. Also removed the ring gear from flywheel.

Anything we I need to check? Is the flaming typical when the engine is revving not under load? I'm pulling my hair out on this one...
 
M

Mariah

#3
#3
A blue flame shows that the air/fuel mixture is right on, if you adjust slightly richer for a touch of orange/red in the flame it will make slightly more power while lowering the combustion temperature in the cylinder which I feel is an all around good thing although it's not mandatory to run rich. Your engine will survive quite well adjusted to a blue flame.
 
ole4

ole4

#4
#4
is the timing correct? Retarded timing causes glowing exhaust and flame out the end. If timing is correct then I would assume itis normal. I have quite a fe hs50's and have never seen your condition.
 
I74

I74

Well-Known Member
#6
#6
Added,,
Air gap seems about right, which is just over .3mm, ''same as Husqvarna solid state ect.''
Do you index your plugs ?
 
Birdball

Birdball

Member
#7
#7
Thanks for the reply guys.

-Exhaust is stock snowblower HS50
-Timing is correct I think- plug gap is good and air gap to magnets is good. Was .0125 as specified, but I just squeezed it to .0100 hoping that ads some advance (is this correct way to advance the solid state?). I did not pull the flywheel, I assume there is nothing under it if I have the top mount solid state?
-haven't indexed the plug

I will check it under load after I put it in the bike, perhaps a free rev with no load wants a leaner condition but under load maybe more rich is what it needs.

Also, With a little more rpm (no governor) if the long flame is where it wants to operate, maybe I need a longer pipe to keep from burning my seat!
 
Birdball

Birdball

Member
#9
#9
No on the rod and flywheel. I will govern myself on this one. I've got a couple other motors laying around and I am going to build up a proper billet rod and performance cam version next.
 
I74

I74

Well-Known Member
#10
#10
Birdball said:
Thanks for the reply guys.

-Exhaust is stock snowblower HS50

Also, With a little more rpm (no governor) if the long flame is where it wants to operate, maybe I need a longer pipe to keep from burning my seat!
Click to expand...
I think an actual pipe would help in more ways than one.
If that stock muffler is pretty burned out inside, you have the potential of not having enough back press. ect,''not enough exhaust'',, & also have a good chance of smok'n the exhaust valve pretty quick, especially with extra revs ect, & then letting off, & getting cold air into the exhaust chamber.
 
I74

I74

Well-Known Member
#11
#11
Added,,
I wouldn't close the air gap.
One trick you can do though for a smidge more advance is:
Long gate the screw holes on the coil a bit with a Dremel or something , so the coil can move some 'towards' the direction of rotation.;)
 
delray

delray

Well-Known Member
#12
#12
you can get little more advance also by machine the threads down only in the area of the coil holes.

if really want to gain some advance timing ,go with a Tecumseh hot coil. the factory runs about 20 and the hot coil about 30 degrees.
 
massacre

massacre

#16
#16
There are many here who are more qualified than me to answer that question, but to me it looks like a ‘76 or ‘86 model year. Does it have points ignition?
 
I74

I74

Well-Known Member
#18
#18
I don't know about that exhaust, why is it right up against the shroud / blower housing ??
Just doesn't look right in the pics,, 'to small' & ''or'' needs a spacer'',, or is it an illusion ??
Is that even the right muffler for it ?
To me it looks like it's for a smaller engine.
 
C

cfh

Well-Known Member
#19
#19
You did a really nice job with that motor, looks great. Personally i don't paint carbs, but that's me (too easy to plug holes with paint, and since it's in constant exposure to gas, could always remove the paint, any paint type.)
And that's a typical Tecumseh stock exhaust that they used for just about any application (well except for minibikes which generally had a Taylor exhaust, which is impossible/expensive to find today.)

 
Birdball

Birdball

Member
#20
#20
Thanks guys- yup- stock snowblower exhaust that I blasted and painted. WRT the carb paint, I was in the fence but just copied what I had seen on another thread.

I'm thinking I will make an exhaust flange and make my own S pipe as I have a tig welder and fab skills.
 
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