Colortune Snowblower

I'm still in the midst of colortuning my Seca, but seeing as winter is here, does anyone have advice on colortuning a Snowblower? Do you do it at idle and full throttle (since this is only like 3000rpm)? I know some members on this site have done it.

 

You are NOT supposed to use a ColorTune at full throttle. Supposedly you could crack the crystal. So I guess that leaves your idle and cold start tune-up.

 

I ColorTuned my SnowBlower.
It's a Toro with an 8Hp Tecumseh Snow King.

It was easy to do.
The Low Speed Jet is like a Pilot Jet.
You let it warm-up and adjust the Low Jet & the Idle Screw.
The Idle Screw simply controls the Throttle Plate.
Get a nice "Sounding" Idle and ColorTune the Low Speed Screw.
When you get Blue you can back-off the Idle Screw and get it to Idle like a Champ.

Then, I was all prepared to make the High Speed adjustment.
I opened the Throttle, spied the Plug, tweaked-it Blue and was done.
It ran at Full Bore for only about 10 or 12 seconds while I made the Mixture adjustment.

Throws soggy, wet, mashed-potato snow a half a block!
I can't wait to rip through a couple of feet of Powder.

 

Worked like a charm Rickomatic (well, I guess the real test will come tonight 8) )! I had to set mine back to the initial settings (about 1 1/4 turn out on both screws) because I'd just been messing with the high speed screw and running it full throttle all last season (you can't get to the pilot or idle screw without taking 3 headbolts off...to get the cover off!). I got a nice blue on the pilot, then cranked it up, saw orange, so I idled it, made an adjustment, then cranked it up, and got a deep blue (it'll be rich-orange, until the engine gets up to speed - about 1-2 seconds). No damage to the colortune.

The actual instructions do explain how to tune off-idle at 2000 rpm in an automotive engine - I doubt the above exceeds these conditions by much.

 

There's another adjustment to make for Power-Throwing Snow.

On the Right of the Throttle Lever is a Small Phillips Screw.
This Screw adjusts the GOVERNOR.
If you are Throwing Snow and the RPM's are pulsating as the Engine hits the Governor ...
Back-off on that Governor Adjustment to have the Engine make Full Power without Over-revving.
A nice steady Full-Power run from one end of the driveway to the other without having to restart the Engine that had a big gulp of snow and had the Governor kick-in is frustrating.

100 - 150 rpm's short of WOT will keep the Power ON ... Steady rather than pulsing as the Limiter catches the Motor going over its Opperational Red Line and knocking-off revs to keep the Connecting Rod --> Connected!!!

 

Hmmm....I've been told not to touch the governor...of course that could be the same as "the carbs are set in the factory don't touch them" advice given on xj's. I've never had the snowblower stop because of the governor, but I did sometimes get the pulsing. I thought this was a carb adjustment issue

 

Alot of lawn - type equipment is governed to 3,600 RPM for legal reasons.
A small boost of RPM is no problem.
An unlimited governor on some odd equipment can cause a failure like a revolving part exploding, then hitting other parts.
A 20 inch lawnmower blade is moving at 180 MPH.
Better think it thru, and be safe.

 

Well it runs good now so I'm not going to touch it...but if anyone knows anything specific about my model, it never hurts to learn 8) . The snowblower is a simplicity from the 80's with a Briggs and Stratton 190433 L-head motor.

 

My point was NOT to have the Engine run at a HIGHER rpm.
The Engine "Surges" because the Engine is reaching an rpm that causes the Governor to LOWER the rpm's and then return to its Full Throttle capacity.

By TWEAKING the Governor, ... you SET the Governor at a Full Throttle rpm that is BELOW where the Governor will be tripped to LOWER the Engine Speed.

When set to sensitively ... the Engine will PULSE at a frequent interval, ... when not under load.
The Engine will do a "DIP", ... Under Load if the the Governor is a Little Bit too sensitive.

But, if you adjust the High-speed Limit to be UNDER where the Governor will Kick-in, ... You will have a STEADY Full Power Operation >> without << the Engine backing-off on the Throttke to bring the rev's down to where the Engine makes Full Power without fear of Over-revving Damage ... because you SET the Throttle at a Limit a little below where the Governor would kick-in to make the Engine lose speed.

 

hmmm...I'm going to have to do this because my snowblower seems to do exactly as you describe, and I was always under the impression that my carb needed adjusting. It surges around when it's not under load, and then when I start throwing snow it runs really strong and steady. At the very least that means I can stop playing with the carbs while I'm snowblowing trying to find the sweet spot. Now I've got to figure out why it's acting like it ran out of gas when it's got half a tank left (i'm thinking either the inline fuel filter-only a year old, or float needle?).

 

I have an older Craftsman snow-thrower. There is no adjustment for the mix so there's no point in colortuning it. The carb is the simplest thing I've ever seen.....a rebuild kit consists of : a new needle, seat, bowl gasket. There is nothing else. The pickup tube is just that- a tube that lets the gas get sucked from the bowl to the intake. No jets, no nothing. Gas goes in, goes, boom, goes out.

Of course, I do need a new drive wheel since this one is now just about worn out...........................

Dave