Tecumseh 7HP Snowblower carb problem

wolfden793 · Feb 15, 2022

Hi All,

I've been having difficulty with a carb on a Tecumseh 7HP snowblower engine, model HSK70 on a Simplicity blower. I bought a new carb and it ran very nicely until I put the metal cover back and then it ran poorly, mainly revved higher. Difficult to adjust once cover is on except for the main jet on the bowl bottom. Suggestions? Thanks!

4get gto · Feb 15, 2022

The cover shouldn't make a difference. Some covers have a hole inline with the low mixture screw for adjusting. Does it run better without the cover on you say ?
Almost sounds like you have a wrong screw in place somewhere. Only wild guesses. Or your cover is sitting somehow to close to carb opening causing it change with cover installed.

wolfden793 · Feb 15, 2022

4get gto said:
The cover shouldn't make a difference. Some covers have a hole inline with the low mixture screw for adjusting. Does it run better without the cover on you say ?
Almost sounds like you have a wrong screw in place somewhere. Only wild guesses. Or your cover is sitting somehow to close to carb opening causing it change with cover installed.

View attachment 733689

wolfden793 · Feb 15, 2022

Hi,

Thanks for your reply. I agree the cover shouldn't make a difference. I've worked on many of these snowblower engines, and none has ever done this. No screws out of place that I know of, just a dome scratcher!

oldnslo · Feb 15, 2022

By runs better is it idling down, flooding out , surging etc?

Richard001 · Feb 15, 2022

Without any photos to see the issue, I would guess that, 1 - the heat cover is blocking the carb intake.
2. The heat cover is interfering with the governor.

Richard

wolfden793 · Feb 15, 2022

Hi Richard,

Thanks for your reply. Hmm, both things worth checking. The guard that is in front of the carb intake spaces the cover from the intake, so don't believe it's coming from there. As to the governor being interfered with, that's a possibility worth checking. Without the cover, I can adjust the carb, although it does surge when the governor screw in turned in. RPM at best setting is about 3100 or so. It's finiky at best, but does run OK without the cover. When I go to put the cover on, I don't even have to put the two carb intake screws on, just get the cover near the intake and it begins to accelerate and won't adjust no matter the position of the throttle control. I welcome your thoughts...

Richard001 · Feb 15, 2022

Can you post some photos of the carb and the governor area ?

wolfden793 · Feb 16, 2022

Hi Richard,

Here are a few pics of my blower. I'll be interested to see what you think.

Richard001 · Feb 16, 2022

Photo #4 shows the float blow vent tube being kinked right at the exit of the carb. You need to change this. Where does the other end of the vent tube go ?
On Photo #7, on the left side of the cover, what does the part that has the sheet metal screw sticking thru it do ?

Can you show photo of the shield installed and look to see if the shield is interfering with the governor arm in that area.

Is this carb an exact replacement part ? For example, did the throttle linkage fit without any bending of the linkage ?