Need help with Toro 2 cycle snowblower CCR2400E that will not run

Joneebgood · 12-31-2010, 01:57 PM

My dad has a ten year old Toro CCR2400E model #38415 snow thrower with a Tecumseh HSK850 2 cycle engine. The first time out each winter it usually runs rough until the gum and old gas clears out but this year it started right up and ran great. 30 minutes into the driveway he said it just stopped dead. Didn’t struggle or surge just stopped hard with a lingering tinny sounding rattle.

It would not start again and the local lawn shop said it needed a carb for $125. Dad is sure the carb was working fine so he brought the snowblower over for me to look at. My Toro has always just run and run and I have never had to work on it so I don’t have much experience with 2 cycle motors. The carb seems clean and normal but the motor will not even run on starting fluid. A very occasional backfire is all. Using the electric starter to crank it over it seems to pulse back out the choke which means it isn’t sucking the fuel in correctly. If I remove the carb and then crank it over it seems like it alternately sucks and pushs air out the engine block. Does anyone know if that is normal or not?

New spark plug and the piston seems to be working fine although there isn't as much compression as I am used to on 4 cycles.

Is there a reed valve or something similar somewhere that could be hanging open? Maybe a valve or vent on the crankcase?

The only other thing I can think of is to replace the coil pack as It doesn’t seem to have any points or other ignition system that cold mess up?

I could buy a carb but I really don’t see how that could be causing the strange pulsating surge from the engine. It we spent for a carb and it still didn’t run Dad wouldn’t be happy.

I would appreciate any thoughts or suggestions what to try next.

jrrdw · 12-31-2010, 02:16 PM

What make engine is on it?

With snow blowers it's hard to tell how much wear and tear it really has on it. Where do you live or rather does it get alot of use each winter? It is possible corrosion in the carburator bowl clogged up the jets. If that's the case simply clean and readjust the carburator and you should be fine.

Here's a good question for you, what kind of 2 stroke oil are you using? That matters because if your using the little pre-measured bottles they all ready have Sta-Ble (spelling) in them. Then people buy Extra gas treatment, add it to their mix gas and wala to much additive and the gas is contaminated to the point where it wont run.

You also have to keep the exhaust port cleaned out, if that gets clogged it wont run. Right where the pipe joins the head. Aclogged pipe will keep it from running.

Joneebgood · 12-31-2010, 02:25 PM

Thanks for the suggestions. The carb is spotless inside. Needle and seat working fine. The clogged exhaust port sounds like a good choice. I assume just remove the muffler assembly and look for carbon?

jrrdw · 12-31-2010, 02:29 PM

Quote:

Originally Posted by Joneebgood

Thanks for the suggestions. The carb is spotless inside. Needle and seat working fine. The clogged exhaust port sounds like a good choice. I assume just remove the muffler assembly and look for carbon?

Yes, shine a light in there and get a good look. Also rotate the engine slowly and look at the side of the piston and make sure it's not scored deeply, some wear marks are normal.

Joneebgood · 01-01-2011, 08:35 AM

I pulled the muffler off and everything looks clear. No carbon and only light scoring visible on the cylinder walls. Could the timing have jumped? There must be a keyway on the crank and on the pulley that I could check to make sure there is no wobble? Is there a test for that or must I pull the engine apart?

Also, what actually makes the spark on a two cycle? I don't see anything ignition related except the coil pack but it must have some kind of points to make and break? Thanks for the help.
JIM

jrrdw · 01-03-2011, 11:13 AM

The coil is behind the flywheel.

Does the spark plug get wet with gas when you try and start it? If not replace the fuel filter, (probably a screen in the gas tank), and the fuel lines then the carb...

If I'm looking at the right manual from www.toro.com this unit has a diaphragm type carburetor. Where the fuel line goes on the carb on the other side of the carb you can take the top/bottom off of it either 4 Philips screws or 1 big straight screw in the center, take them off and inspect the diaphragm, the little screen, squirt it all out with carb cleaner.

Joneebgood · 01-06-2011, 04:27 AM

Thanks for the suggestions, This unit has a fixed carb. The brass bolt holding the bowl on acts as the main jet. There is no idle or any other adjustment and no diaphragms or restrictions. It looks like, as long as the needle and seat are functioning, there is nothing else that should cause an issue with the carb.

The plug seems to stay dry but there is lots of gas in the spit cut. This engine has just as much outward pressure on the carb as there is on the exhaust port so it seems that it sucks up some fuel but the fuel doesn't get into the engine before some pressure blows it back out to accumulate in the spit cup.

As best I can tell the compression is about 60psi which I am told is the lower limit for these engines to function so I guess I will pull the piston and see what I find. There is quite a bit of scoring evident. I know poor compression should not have stopped it dead when it was running great and had lots of power but maybe it broke a ring or something? Something is causing too much crankcase pressure and I think that is what is pushing the gas back out the carb instead of sucking it in.

This is not a reed valve engine but just has drilled passages for intake and exhaust that uncover as the piston travels. If there is too much blow-by perhaps it creates too much pressure in the crankcase and pushes the fuel back out instead of sucking it in?

The plug shows good strong spark but the engine will not run even on starting spray. Just an occasional backfire so I don't know what else try. The coil looks to be passing the magnets just about TDC so I don't think the shaft key has sheered.

Thanks for your suggestions.

jrrdw · 01-06-2011, 11:06 AM

A heavily scored piston can hold the rings from expanding as they should and cause the problems your describing. You might have a hard time finding over sized parts for this engine, I would check into it before spending any money on this etc...