FasTrak SD with Honda GXV630 stumbles at full throttle.

[FasTrakSD]

Hello,

I have a 2013 Hustler FasTrak SD with Honda GXV630 (with 175 hours) that stumbles at full throttle. I run ethanol free fuel, completely disassembled and cleaned the carburetor and sanded the surface rust off the flywheel. It idles wonderfully and runs great to about 1/2 to 3/4 throttle but stumbles at full throttle like a street-bike bouncing off the rev-limiter. I'm not sure if it's a fuel or ignition problem. Any suggestions?

Thanks in advance.
Cliff

This issue has been resolved! Scroll down to see full explanation.

 

[mechanic mark]

RESULTS OF RUNNING ETHANOL FREE GASOLINE IN SMALL GAS ENGINES - Google Search

I use 93 octane gasoline with Star Tron Fuel Treatment in my 2010 Simplicity with 20hp Vanguard engine.

star tron - Google Search

 

[bertsmobile1]

Change the plugs
Run the engine without the blower housing on in the dark working the governor arm with your finger.
Watch closely for stray sparks.
Keep it to under 5 minutes .
Take the kill wires off the coils, put the blower housing back on and see what happens.
Naturally if you see sparks then that needs to be addressed.
If the removed wire cures the problem then you have a short in the safety wires or a duff switch

 

[FasTrakSD]

Change the plugs
Run the engine without the blower housing on in the dark working the governor arm with your finger.
Watch closely for stray sparks.
Keep it to under 5 minutes .
Take the kill wires off the coils, put the blower housing back on and see what happens.
Naturally if you see sparks then that needs to be addressed.
If the removed wire cures the problem then you have a short in the safety wires or a duff switch

Thank you. I'll try these things you suggest and report back my results.

 

[FasTrakSD]

This issue has been resolved!
After exploring all the suggestions with no improvement I decided to go with my gut and order a new set of OEM factory ignition coils. This is what I thought it was from the beginning but I really didn't want to spend $360.00 and be wrong.

I installed a digital tach and saw that it would rev to 3000 RPM and be fine but beyond that the rev limiter would kick in. Pretty sophisticated little coils with the built-in advance timing and rev-limiter circuitry. I was just about ready to scrap the Honda in favor of a Kawasaki engine if the new coils didn't work.

I also found that the #2 cylinder has plenty of clearance for it's coil but the clearance for the #1 cylinder coil was not centered on the coil's location and had one cooling fin within 1/4" of the coil. Being concerned about heat concentration in that one spot I removed the cooling fin. Where the cooling fin was located at the base of the cylinder I'm sure it won't be a problem.

On the bright side, I have all new jets, nozzles, o-rings and fuel screen, etc. in the carburetor; new sparkplugs, filters and proper valve clearances and now new ignition coils. It just turned 200 hours and I'm hoping it will be trouble free for a good long time (aside from regular maintenance).

I hope this helps someone else in the future.

 

[slomo]

Clean the block and cooling fins while you are there.

Might pull the head/s off next winter to decarbon the cylinder/s and valves.

 

[FasTrakSD]

Clean the block and cooling fins while you are there.

Might pull the head/s off next winter to decarbon the cylinder/s and valves.

The engine and cooling fins are clean. The heads and cylinders are integral (all one piece). Is decarbonizing a common thing? is it really necessary? It seems like a lot of effort, what’s the reward?

 

[slomo]

Is decarbonizing a common thing? is it really necessary? It seems like a lot of effor, what’s the reward?

Stopping engine damage. Yes it is necessary. Chunks of carbon can dislodge and get between the piston and bore. As well as it gets behind the valves causing the valves not to seal. Common wear does that too.

Cleaning the fins and decarboning is in every engine manual.

 

[cwtex04]

I’ve had to replace ignition coils on my Mini Fastrack with the 16hp Gxv530 . I just put the second set on last week. I have approximately 1400 hrs on the unit . Last time I changed them was about 5years ago . Pretty good considering unit is about 16 years old .

 

[FasTrakSD]

I’ve had to replace ignition coils on my Mini Fastrack with the 16hp Gxv530 . I just put the second set on last week. I have approximately 1400 hrs on the unit . Last time I changed them was about 5years ago . Pretty good considering unit is about 16 years old .

I would have replaced them sooner had they not been $160 each. The cost of the coils is outrageous in my opinion. I was considering swapping out with a Kawasaki, but now that it's fixed I'm once again happy with the Honda. So your coils lasted about 700 hours for each set, that's pretty good. Mine went out at 175 hrs, way too soon if you ask me. Thanks for your response.