Throttle Response

[lone wolf]

Thanks all.

Since the saw in question is an older Husqvarna similar to another I have which performs better, I am still leaning toward carb adjustments being the culprit.

Carb parts such as diaphragms are new.
Seals check out in both vacuum and in pressure.

I can definitely double-check linkages. I guess slop there could cause problems for sure.

Did you open the muffler up a small amount it could be restricting.

 

[mountainlake]

I'm old and slow, never had a saw that didn't rev up fast enough. Just pull the throttle a split second sooner. Steve

 

[ballisticdoughnut]

Thanks all.

Since the saw in question is an older Husqvarna similar to another I have which performs better, I am still leaning toward carb adjustments being the culprit.

Carb parts such as diaphragms are new.
Seals check out in both vacuum and in pressure.

I can definitely double-check linkages. I guess slop there could cause problems for sure.

What model is it?

 

[Vintage Engine Repairs]

How does one get the best possible throttle response from a saw? I want my saws to leap into action when I trigger 'em.
What variables affect it?

I have a particular saw is cold blooded. It starts and runs great, but when it's cold throttle response is weaker. After warming up, it is more snappy. I of course warm all my saws before really getting on the throttle or loading them.

Tell me if I am wrong...things that affect it:

1 ) L screw. Should be a little rich?
2) Chain and chain lube and chain size, i.e. weight and chain friction, stuff that takes energy to get things going?
3) Idle speed? Faster idle jumps more on trigger press?
4) Design of engine such as "blowdown" and stuff like that?

Thanks

I did this video a little while back, hope it helps

This may help too.

 

[StihlPotlicker]

Until they go bad.

I like the old pre-limiter carbs.

I like my old truck with a manual choke that I can work on with simple tools, even if I have to warm it up and be careful cold weather not to flood it. Todays kids are baffled with a car/truck choke, soon they won't know what a clutch does..........

a what? LOL just kidding I miss driving stick.

 

[Farmer_Nate]

Saw is a 266xp

88-89 model?, not the older SE

 

[Farmer_Nate]

I did this video a little while back, hope it helps

This may help too.

I saw that video a few months ago. It is very very nice. I need to watch again more slowy and carefully. Thanks

Great work.

 

[stihltech]

Nitrous.

 

[Vintage Engine Repairs]

I saw that video a few months ago. It is very very nice. I need to watch again more slowy and carefully. Thanks

Great work.

Thanks for the kind words

 

[Mad Professor]

You went it set just rich enough it doesn't lean bog when you crack the throttle.
This is another reason MTronic/Autotune is a good thing.

Yup!

 

[Farmer_Nate]

Thanks for the kind words

PM sent

 

[Farmer_Nate]

Cut with that saw this evening for 2 hours. It is a fine running saw when full-on cutting, just not as snappy on the throttle as my others.

I have the muffler opened WAYYY up, probably excessively, so I wonder if that could be doing it. It essentially does not have a muffler right now. I have a project planned for that muffler to put a slightly more restrictive apparatus on it, but I am tied up with other things right now. When I choke it back down to about 70-80% of the exhaust port opening maybe it will straighten out. I have it probably 100% right now.

 

[Farmer_Nate]

Tuned the saw a bit more. It is more snappy.

Problems I found:

1) slop in the throttle linkage. I eliminated slop. Put electrical shrink wrap around a wire control rod which snapped into a plastic C-shaped clip thingy. Throttle trigger has no initial movement or take-up before moving the butterfly.

2) L screw was too lean

 

[chilipeppermaniac]

this is a deep rabbit hole of a question.

for the variables already mentioned how could one not also consider that rotating mass plays a part......and then for that matter too what about the throttle linkage i.e. push rod (357xp) vs. roller push rod (242xp) vs. cable (372) vs. others?

Not only those variables, but what is the overall health of this saw?
I would first try to diagnose if it has a problem which is causing the sluggishness. Air leaks, Dirty air filter/ Carb, Fuel Filter, fuel line clogs/gumminess.

If saw is healthy, then a properly set carb is a good start.



Watch here from at about 5 minutes+ to about 15:30+

 

[sean donato]

Until they go bad.

I like the old pre-limiter carbs.

I like my old truck with a manual choke that I can work on with simple tools, even if I have to warm it up and be careful cold weather not to flood it. Todays kids are baffled with a car/truck choke, soon they won't know what a clutch does..........

Comments like this make me laugh. Your on a phone/computer to respond to a internet forum, but your scared of m-tronics.
It's a carb with a fuel selinoid on the side of it and all of 3 sensors. None of which are any more advanced then the electronic ignition on your truck. Even the coil for m-tronics is as dumb as a brick with little to go wrong, that won't go wrong in any solid state ignition. Most the issues with them is the same as a normal carb saw. Its not rocket science or voodoo.

 

[Farmer_Nate]

I appreciate the saw tuning videos.
I think saw is fine now with more L screw and less slop in the throttle linkage.
Saw is healthy, recently rebuilt seals and carb.