# Carburetor adjustments



## AL- (Oct 27, 2014)

I put a new repair kit in my HM80 Tec carburetor however I left the float spacing as it was although it was a bit wider than the gap required by the Tecumseh carb tool. I set the main jet needle out 1 1/2 turns but when tried to adjust engine when running I can screw the needle in 1 1/2 turns and engine keeps on running the same as when its out 1 1/2 turns, also the primer floods it easily. The engine starts good and runs fairly well. I wondering if I need to set the float gap more accurately in order to be able to adjust the carburetor and make it less prone to flooding when priming. Thanks for advice.


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## Jackmels (Feb 18, 2013)

Sounds like you may have the Wrong Size Needle. Needle adjusted all the way Tight will stop the flow of fuel if it is working correctly.....When Carb Problems Happen, I Usually just get an adjustable jet repop carb on ebay, Only 20 bucks or so, Bolt on and Problems GONE...Russo Power usually has decent prices. I keep an extra one on the shelf. GL.


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## GoBlowSnow (Sep 4, 2015)

Ditto, Jack. I'm the same way. Get a new one.


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## cpchriste (Jan 19, 2014)

Your symptoms indicate the passages inside the carb body are still dirty. Either soak and blow/ream them out or buy carb as suggested.


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## Marty013 (Mar 14, 2014)

air leak?? ive had this issue... needles not showing response.... and the end results are not good... 

check air leaking somewheres between carb and block... intake to carb gaket, intake to block gasket... block to head gasket...


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## AL- (Oct 27, 2014)

The main jet is new and the needle can be screwed in tight and still it keeps on running . Also I have ran it with a small amount of gas and just before it runs out of gas it rev's up and runs smooth. I think this means its runs too rich.


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## thool (Jul 25, 2016)

I'd compare the new and old brass nut the main needle valve screws into. I recall reading that the side hole configurations vary, so you might be running into a mixture issue associated with that.

Also, just confirm: You're adjusting the main needle valve when the engine is running at or near full speed, correct?


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## GoBlowSnow (Sep 4, 2015)

Good point, thool. I learned that lesson recently on a rebuilt carb. I put in the brass nut that came with the rebuild pack and I could not get the thing tuned right. Put in the old brass nut with the new jet, and it purred beautifully.


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## AL- (Oct 27, 2014)

thool said:


> I'd compare the new and old brass nut the main needle valve screws into. I recall reading that the side hole configurations vary, so you might be running into a mixture issue associated with that.
> 
> Also, just confirm: You're adjusting the main needle valve when the engine is running at or near full speed, correct?


Running it warm at around 3000 rpm. I just took the carburetor apart cleaned everything , set the float at the right height but no change, I can screw main needle in all the way and it runs but it runs rough, and just before it runs out of gas it speeds up and runs smooth.


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## GoBlowSnow (Sep 4, 2015)

You need to get that up to 3400-3500 RPM.. Speed of the engine makes a difference as well.


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## thool (Jul 25, 2016)

AL- said:


> Running it warm at around 3000 rpm. I just took the carburetor apart cleaned everything , set the float at the right height but no change, I can screw main needle in all the way and it runs but it runs rough, and just before it runs out of gas it speeds up and runs smooth.


Just for giggles, do as GoBlowSnow suggests and try the old brass nut. Also check the gaskets between the carb and block (sometimes there are spacer bodies). I had a leak there once and it wasn't pulling enough vacuum to make the high speed adjustment work properly.


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## GoBlowSnow (Sep 4, 2015)

Yet another good point, Thool about the gasket.


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## AL- (Oct 27, 2014)

thool said:


> Just for giggles, do as GoBlowSnow suggests and try the old brass nut. Also check the gaskets between the carb and block (sometimes there are spacer bodies). I had a leak there once and it wasn't pulling enough vacuum to make the high speed adjustment work properly.


for giggles... cleaned and used the old brass nut, cleaned the surfaces where gaskets go by rubbing them on plate glass & 420 grit sandpaper, also put a very thin coating of non hardening gasket maker on both sides of each of the gaskets. I can screw main needle in until tight and it still runs rough at 3400 rpm.


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## unknown1 (Dec 13, 2015)

Hmmm.. not my specialty but if you totally remove that needle, does it have a spring and a brass collar and a rubber oring? If so, does the oring look ok?

Just a thought.


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## AL- (Oct 27, 2014)

stuart80112 said:


> Hmmm.. not my specialty but if you totally remove that needle, does it have a spring and a brass collar and a rubber oring? If so, does the oring look ok?
> 
> Just a thought.


Sorry for the slow response, problem with computer. The O ring looks ok and was new and no leaking from around needle.


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