Snowblower surging up and down

[viperv10]

Ok , thank you.
Another thing is that since it is dark already outside there is white flame coming out of the muffler. I thought that was strange.
The muffler has one of its mounting bolts missing but is still tight and flame comes out that bolt hole too.
I am going to swap out carbs and see what happens. I have a new gasket that I will use.
If that doesn't work it might be off to the small engine shop.
Thanks for responding guys.

 

[Scrubcadet10]

Definitely running lean, then.

 

[viperv10]

Well I installed the rebuilt Tecumseh carb and didn't help a bit. Still surges. But it runs pretty good on half choke.
Too bad they don't have any adjustment screws to help with the mixture. It might run ok on half choke. I will just have to try it out if we ever get enough snow.
Jerry

 

[lefty2cox]

I recently fixed a similar problem on the same engine, an LH318SA. I threw 3 carbs at this one, a thoroughly cleaned original, and 2 aftermarkets...still surged. Someone on a forum suggested the valves may be causing my surging. I didn't fully understand the connection but figured I had nothing to lose. I checked and there was no clearance on the exhaust valve. I too had flames. I did a valve job and both the flames and surging went away.

Double-check me with your serial but I think the head gasket is 36448. I'm not sure how handy you are but given what you've done so far, it's within your wheelhouse. Sounds more complex than it is.

 

[viperv10]

My serial # is 156596H or actually that's the spec #. There isn't a serial number listed on the sticker. Yes, according to Jack's Small Engine search that would be the right head gasket. Does the head need to come off to the adjust the valves? I'm a Lawn Boy guy and mostly tinker with 2 strokes. I did work on a B&S engine on a power sprayer
once. It wouldn't start and I found out that the valves weren't moving. So I opened it up and found that it had plastic cam that was shot. I mostly just clean carbs on 4 cycle
engines. I guess I could always watch a youtube video.
Thanks for the tip and for replying.
Regards

 

[Rivets]

Another thing to try is readjusting the governor. If it is out of adjustment it will cause surging. This manual may be of some help. https://www.mymowerparts.com/pdf/Te...P-4-CYCLE-L-HEAD-FLAT-HEAD-ENGINES-692509.pdf

 

[lefty2cox]

My serial # is 156596H or actually that's the spec #. There isn't a serial number listed on the sticker. Yes, according to Jack's Small Engine search that would be the right head gasket. Does the head need to come off to the adjust the valves? I'm a Lawn Boy guy and mostly tinker with 2 strokes. I did work on a B&S engine on a power sprayer
once. It wouldn't start and I found out that the valves weren't moving. So I opened it up and found that it had plastic cam that was shot. I mostly just clean carbs on 4 cycle
engines. I guess I could always watch a youtube video.
Thanks for the tip and for replying.
Regards

I apologize for the late reply, I thought I had set it up for email notification. You may have moved on or already done it but yes, the head has to come off and the valves have to be removed. There are several videos on the tubes that will walk you through it better than I can. Just search Tecumseh flathead valve adjustment.

 

[StarTech]

First idle mixture jet must cleaned and then fully screwed in. The bowl retaining bolt/nut is also the main jet it also must cleaned. When either partially clogs they lean the mixture. Finally it might necessary to resize these jets. Usually I recommend letting someone that has done this before to do it as you can easily oversize them and cause an overrich mixture.