# HS724 rough when cold?



## Dhark (Sep 19, 2021)

Hey guys need help diagnosing a problem with my HS724. Machine tends to sputter upon startup for a few seconds then seems to run great. But if I engage either the drive or augers it will sputter and die. If I let it warm up a for few minutes its fine? I did a complete carb tear down and clean when I got it and did the same thing before I put it away for the year, so I really don’t think it’s the carb. Any idea on what to check next? Spark plug looks good and I just don’t understand why it runs fine when warm and not when cold? I’m stumped?


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## Tony-chicago (Feb 10, 2021)

First thought is a very lean condition. Several causes.


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## JLawrence08648 (Jan 15, 2017)

I go back to carb.

Does it have a Welch plug? If so, remove that, use carb cleaner, then a welding tip cleaner.


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## Dhark (Sep 19, 2021)

JLawrence08648 said:


> I go back to carb.
> 
> Does it have a Welch plug? If so, remove that, use carb cleaner, then a welding tip cleaner.


I don’t think Hondas have Welch plugs


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## nitehawk55 (Sep 9, 2021)

Sounds a bit lean to me as well. The way it's running sounds like the carb is off a bit , maybe some crap in the main jet..


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## Tony-chicago (Feb 10, 2021)

Wonder if a full tank helps or not. Shouldn't but have seen it happen with a low tank.


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## Dhark (Sep 19, 2021)

Tony-chicago said:


> Wonder if a full tank helps or not. Shouldn't but have seen it happen with a low tank.


It is a little low. I just did a quick clean of the carb. Took main and pilot jet out and they were both clean, bowl was immaculate! Choke works fine, Still sputtered at start up. Gonna fill it up with fresh gas even though the stuff in there is treated. I don’t think it’s the spark plug but maybe I’ll change that out too.


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## Tony-chicago (Feb 10, 2021)

Or possibly a small air leak somewhere


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## Freezn (Mar 1, 2014)

Make sure you clean the main jet and emulsion with a small strand of copper wire. They might look clean to the naked eye or even a quick blast of carb spray, but you would shocked how many times I find partially clogged holes in the main jet that require clean up with thin piece of wire.


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## Dhark (Sep 19, 2021)

Freezn said:


> Make sure you clean the main jet and emulsion with a small strand of copper wire. They might look clean to the naked eye or even a quick blast of carb spray, but you would shocked how many times I find partially clogged holes in the main jet that require clean up with thin piece of wire.


Did that all clean, every single hole was poked. Can see clear thru them all.


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## orangputeh (Nov 24, 2016)

take the plug out and what does it look like?
can you post a pic of it?

Have seen coil problems with 724's more than any other model Honda for some reason. I would check air cap if plug is normal.


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## Dhark (Sep 19, 2021)

orangputeh said:


> take the plug out and what does it look like?
> can you post a pic of it?
> 
> Have seen coil problems with 724's more than any other model Honda for some reason. I would check air cap if plug is normal.


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## nitehawk55 (Sep 9, 2021)

Black ans sooty , looks to be rich.
When the insulater has a buildup like that the plug can arc to ground and cause misfire.


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## Dhark (Sep 19, 2021)

nitehawk55 said:


> Black ans sooty , looks to be rich.
> When the insulater has a buildup like that the plug can arc to ground and cause misfire.


What would cause that? There are no adjustments on the carb so how is that fixed? Would that only be a problem when it’s cold and be fine when warm? Could that be the wrong spark plug in it?


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## nitehawk55 (Sep 9, 2021)

Are you seeing any black smoke from the exhaust ? Some for just a bit when you start it cold with the choke on is normal but that won't cause a buildup on the plug insulator like that . It's possable you have a cold plug in it , check on that . High float setting could make the carb rich .


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## CarlB (Jan 2, 2011)

doesn't look lean to me, it looks rich


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## Yanmar Ronin (Jan 31, 2015)

The plug looks old... I'd try a new one, clean and properly gapped.

It does look black but that could be because the spark isn't hot enough.


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## JLawrence08648 (Jan 15, 2017)

Yes it looks rich, carb problem or spark plug is old. Do not replace the spark plug with a hotter one, it may cause detonation, pre-ignition, burning a hole in the piston head. 

Replace the BPR5es with the same.
Remove and clean the carb.
Clean the coil contacts, flywheel magnets, ignition coil grounds.
Put up with it.


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## orangputeh (Nov 24, 2016)

"works fine when warmed up "

clue


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## aa335 (Jan 21, 2020)

It's a German made car!


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## Dhark (Sep 19, 2021)

orangputeh said:


> "works fine when warmed up "
> 
> clue


Solutions?


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## ssls6 (Sep 25, 2019)

Sputters when cold
Runs when warm but no load
Dies with load
Sooty plug

A couple of things to check:

I would check the float....is it shutting off at the right height (likely isn't it but I would check)
I would check the linkage/govener to see if the throttle is opening up with load (take the breather off so you can see). If this isn't working right it would die under load.

Good luck


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## orangputeh (Nov 24, 2016)

Dhark said:


> Solutions?


Wish I could be there in person. Could be a number of issues. I just read your post again. You said everything runs fine when it is warmed up? Does that mean it does NOT sputter and die under load? It's only when cold?

Assuming the carb is clean , I would remove air box from carb and inspect choke function and make sure the choke opens up all the way. It could need an adjustment which is fairly easy. Is the choke plate sticking? With the choke off the plate should not be partially closed at all. 

Also did you replace carburetor gasket when installing? Is it sealed well? You can test by running engine and spraying carb cleaner around both ends of carb where the gaskets are and see if engine changes speed. If so then you need to either change gasket or see why you are not getting a good seal. 

choke and seals are easy to check. I always go with the simplest stuff first and then work my way up ( again assuming that the carb was cleaned correctly )


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## Dhark (Sep 19, 2021)

orangputeh said:


> Wish I could be there in person. Could be a number of issues. I just read your post again. You said everything runs fine when it is warmed up? Does that mean it does NOT sputter and die under load? It's only when cold?
> 
> Assuming the carb is clean , I would remove air box from carb and inspect choke function and make sure the choke opens up all the way. It could need an adjustment which is fairly easy. Is the choke plate sticking? With the choke off the plate should not be partially closed at all.
> 
> ...


I know right, it’s so hard to diagnose from across the country. Lol. I’m gonna change the plug for shits and giggles. I’ve cleaned the carb real good. Even put in in an ultrasonic cleaner so I know it’s clean. I reused the gasket as it was in good shape but I’ll check it again. Fresh fuel. And yes once it’s warmed up it’s all goof no sputtering, backfiring or stalling under load. It doesnt even have to warm up all that long. Maybe a minute or 2. Choked appeared to be working fine and not sticking. I’m at a loss


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## nitehawk55 (Sep 9, 2021)

Same here , hard to diagnose without seeing it. TRy a fresh plug and check it after running a while to see if it gets sooty again . I think I mentioned that if the insulator is dirty it can arc and cause misfire.
The carbon acts as a conductor and under compression can do all sorts of wierd stuff.


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## orangputeh (Nov 24, 2016)

Dhark said:


> I know right, it’s so hard to diagnose from across the country. Lol. I’m gonna change the plug for shits and giggles. I’ve cleaned the carb real good. Even put in in an ultrasonic cleaner so I know it’s clean. I reused the gasket as it was in good shape but I’ll check it again. Fresh fuel. And yes once it’s warmed up it’s all goof no sputtering, backfiring or stalling under load. It doesnt even have to warm up all that long. Maybe a minute or 2. Choked appeared to be working fine and not sticking. I’m at a loss


so you eyeballed the choke function? "appeared to be working fine " sounds like guessing.


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## Dhark (Sep 19, 2021)

orangputeh said:


> so you eyeballed the choke function? "appeared to be working fine " sounds like guessing.


How else do you check it? Push choke forward shuts butterfly, pull choke back opens butterfly? It’s manual choke am I missing something?


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## Dhark (Sep 19, 2021)

Update. I took carb off again and even though it was spotless I ran it through the ultrasonic cleaner. Got 2 new paper gaskets and the metal spacer gasket. New Oring for pilot jet and sediment bowl, and new bowl oring. Pulled valve cover off to inspect rockers and it seemed fine (super clean and nothing loose), replaced that gasket as well. Also new spark plug. That all did the trick. Only 2 things that seemed off were the pilot jet oring was a little disfigured and the metal spacer gasket also seemed a bit worn? Maybe it was 1 of those thing or maybe it was just the plug? Either way it’s fixed and I sold it, I much prefer my 828 wheeled unit better


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## orangputeh (Nov 24, 2016)

Dhark said:


> Update. I took carb off again and even though it was spotless I ran it through the ultrasonic cleaner. Got 2 new paper gaskets and the metal spacer gasket. New Oring for pilot jet and sediment bowl, and new bowl oring. Pulled valve cover off to inspect rockers and it seemed fine (super clean and nothing loose), replaced that gasket as well. Also new spark plug. That all did the trick. Only 2 things that seemed off were the pilot jet oring was a little disfigured and the metal spacer gasket also seemed a bit worn? Maybe it was 1 of those thing or maybe it was just the plug? Either way it’s fixed and I sold it, I much prefer my 828 wheeled unit better


Thanks for update. It's always good when it's finally right.


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