I have a 98 Toro 5 horse ccr2500 single stage snowblower. Model 38422. It has the Tecumseh R-tek motor. The carb has been gone through twice and is as clean as whistle. It has a new plug and great spark. It will fire right up on one pull and stay running just fine. Here is the problem while running when there is no load it surges (rpm drops then recovers) every 5 seconds or so. It does matter if auger is engaged or disengaged. But under load while plowing snow it stays completely steady with no surging at all. Is there a way to correct this so that it runs smooth all the time?

Thanks for your help

 

Bad or wrong octane gasoline ?

 

I put all brand new gas/2 stroke oil in it. I put in the lowest 85 octane. I have never seen a lawn/garden machine require mid grade or premium? I'll give it a shot.
Thnks for the suggestion

 

It may be a governor problem and running to fast under no load.Is It a 2 or 4 cycle if it is a 2 cycle they never sound to good on a snow blower that is not under a load.

 

It is 2 cycle. It has a fan governor( I think that what it is called) that pushes away as the flywheel spins and creates wind. It moves freely so I don't think the problem is there. The governor spring also looks to be in good condition.

 

I couldn't find much on their website.
Do you have the owner's manual ?

 

Sorry the engine is made by briggs and stratton. Yes I have the owners manual as well all the engine tear down pics and a 65 page r-tek engine manual.

You can view tear downs/owners manual on toro's sight. click on homeowner and then product center. Enter the model # 38422 and select the 1998 model. You can see everything.

 

I agree, Try lowering Your idle RPMs. The float level could be set to high also.

Frank

 

I checked the idle rpm.
No load=4040rpm loaded=3980rpm
The service manual says rpm for this should be 3800 +-300rpm. So it is whithin the proper limits. I will check the float.

 

A few suggestions:

Enrich the mixture at idle. Not much. One way to tell if this will work, is to close choke just a bit. This might help. If it does, adjust carb to enrich air/fuel mix without choke being partially closed. 1/8 to 1/4 turn (open) should be sufficient.

Governor (if plastic vane) might have a 'burr' on the bearing surfaces where it is mounted. Remove burrs with 320 grit sandpaper.

Last suggestion. . . . .

An old friend had an engine that wouldn't idle for anything. Nothing would work. (This was an old Clinton engine.)

He used a 35mm film can and made an oil damper.
He filled (about 1/2 full with 3-N-1 oil and made a piston with a washer, a small piece of steel rod, threaded, and a nut above and below the washer and the film can lid w/ a hole in it. (Close fitting to make a bushing.)
The film can was mounted to the engine with a 'band' and screw.
Attach rod to carb with either linkage or spring.
With the can mounted so that the washer 'piston' is submerged in the oil, this will dampen the carb and end the surging.

That 'gizmo' was the darndest thing I had ever seen. And it worked!!!
That Clinton engine would idle down to a putt. . . . putt. . . . putt. . . .


Just a thought. . . . . . . . .

 

This has a Plastic composit carburetor and there are no adjustments at all. You can't adjust the idle speed. The mixture screws are simply metered so that you can't adjust these either. Darn these emmision complient carbs.

The entire piston/ film canister idea sounds interesting. I tried to acheive the same thing with springs pulling from both sides of the throttle and it worked ok but I decided to take it off and try to figure out the exact problem.

Here is what the repair manual says under troubleshooting

~Engine Surges~
PossibleCauses--------------------------Remiedies
Fouled idle circiut-------------------------Clean idle circiut
Air leak-----------------------------------Check sealing surfaces
Restricted fuel flow------------------------Check hoses and filter
Engine rpm low----------------------------Check and set to factory settings
Governor linkage misadjusted---------------Check and adjust
Air vane sticking---------------------------Clean

I know my way around an engine but I have no idea what an idle circuit is or how it gets fouled. I checked and rechecked for air leaks, non were found. I took the fuel hose off the carb and fuel flows out very quick. Engine rpms are on the high side so they are not low. I fiddled around with the governor linkage (you are supposed to bend it to mak it longer or shorter, crappy design if you ask me) and it helped a tinny bit. The air vane doesn't seem to be sticking but I have taken the air shoud off yet (todays project).

 

sixtyfive_ford,

I've never fooled with 2 stroke engines (much) but, I've been inside/outside 4 strokes for years.

To me, the high idle and pulsing sounds like too much air, not enough gas.

I might have missed the post, but, have you cleaned the carb?
Take that puppy off and dunk it in some kerosene and let it soak for 24 hours, if not.

I too dislike the fixed carbs. (Nothing like being able to 'tinker' with something to make it 'right', ya know. . . . .)

I was going to suggest the gas filter, but, if the gas is flowing (as said above) there's no point to that.



Other than that . . . . . .????????????????????????????????

 

I ripped into the entire thing again today. The float was set a tad high so I corrected it. While I was in the carb I thoroughly cleaned it for the third time. The governor air vane moves very easily with no sticking. Tried running with half choke then 1/4 choke. I lowered the engine rpms. All these things and it still surges. Could it be running to rich? It takes a 50:1 ratio and while it was running and warmed up it was slightly emitting white smoke. Generally when 2-strokes are completely warmed up they don't smoke.

 

I have a Toro CCR2450 two stroke R-Tek motor and it is doing exactly the same thing. Otherwise it is in overall excellent condition in all respects. I took the rear shrouding off and I can observe the plastic throttle lever moving back and forth. There is a definite pattern that keeps repeating in intervals that are far too regular for me to believe it is not normal. The fact the the rpms stabilize when plowing would be another factor suggesting this is normal. I just got mine and have not plowed any snow with it yet. I moved the throttle lever with my fingers and it moves quite freely (nothing binding it) under spring tension that also seems normal. None of this happens with the choke fully on, so maybe there is a richness issue and maybe this is causing the governor to behave this way. The whole thing is very eery. It is not normal, but the throttling up and down is so consistent that I am starting to believe it is normal.

 

This is making me wonder if this is common with Tecumseh engines. I had a Murray riding lawn mower with an 8 HP Tecumseh and it would surge like this while unloaded but once loaded it performed perfectly smooth. I read somewhere that it was likely a governor problem more than anything else.