Too much compression in my Toro SR-210SB

[Anachronomer]

Hello. I tried to start my Toro SR-210SB (The only information on the engine I can find is that it is a "GTS-200 OHV", I can't find the manufacturer) for the first time this spring and found that if I pull fast on the starter rope, it refuses to turn over. If I pull slow and hard, I can get it to turn over, but it is very difficult. I can not crank it fast enough for it to even try to start. I removed the spark plug, and with the plug out, it cranks smoothly and easily. Based on that, I assumed that a valve was stuck. I pulled the rocker cover off, and noticed that the valves move freely. I pulled the cylinder head off and found that the piston and valves look super clean and move perfectly. That exhausted my troubleshooting ability, which is why I'm here.
To summarize:
- Very hard to turn over with spark plug installed
- Turns over smoothly and easily with spark plug removed
- Valves are clean and move well.
- I'm over my head with this one.

The only additional details that I can think might possibly be related are that I stored it over winter in a shed instead of the garage, but either way it always freezes over winter. It didn't get wet or anything like that.

Thanks for any help or suggestions.

 

[motoman]

Dear sir, your name alone deserves response. I cannot help you directly, but I just had similar experience with (get ready) my 2 stroke Husky chain saw. Relevant? Probably not..
I almost broke my arm pulling (with compression release). I finally concluded two things were at work. I never oiled the piston/rings before shut down one year ago, and feel some rust had formed, but did not confirm it. Next using fresh gas oil , but richened for trimmer ratio , I was fouling. As noted, you have a 4 stroker, but check for old , gummy gas ,spark.
The sensation was "trying to fire but not quite."

 

[chance123]

I believe your engine is made by Suzuki The "GTS" (Guareenteed To Start) has a compression release. Have you checked your valve clearences? If the gap is just a little too much, the compression release will "not" activate.

 

[Rivets]

Check the oil level, but it is way above full. Also pull the plug and ground the spark plug wire. Slowly pull the engine over. Tell us what happens.

 

[Anachronomer]

Hi all. Thanks for the replies. Of course, we decided to go out of town today through this weekend, so I won't be able to work on it until sometime next week. I'll try the suggestions and post back as soon as I'm able (or as soon as I figure out how to put all of the bits back together again).

My name is a play on anachronism - my wife tells me that I live out of my own time.

I'm looking through the parts manual for this, and it doesn't show me (that I can tell, anyway), where I would check/adjust the valve clearances... I'll have to do some more research there.

For what it is worth, the oil level was spot on before I took it all apart. Given how much I've wiped off of the deck while taking it apart, it is probably a little low now. How would I go about grounding the plug wire? Will I damage the connector with an alligator clip?

Thanks again.

 

[Rivets]

Alligator clip will work fine. I'm thinking you have a cylinder fill with fuel tha won't compress. Don't want a spark when you tun it over.

 

[Anachronomer]

Ok, I checked the valve clearances, and they were slightly out - .003 for the intake and .009 for the exhaust. I adjusted them both to .006 (the service manual says to have them between .004 and .008, so I aimed right for the middle... should I prefer one end or other of the specified range?).

With the spark out and the wire grounded, it spins freely as fast as I want to pull it. Once the spark goes in, it is still nearly impossible to turn over, and it is all I can do to pull it through the compression stroke very slowly. On the bright side, my arm is getting a great workout. The cylinder is empty and clean, and there isn't any fuel to go in it because I have the tank pulled off and lines drained. The surface of the piston is clean as well.

I believe that my next step is to pull the cam out and check the compression release? Anything else to try first?

One side question... How important is it to replace the gaskets when I pull the valve cover and head? The gaskets that are in there now look OK to me, but I don't really know how to tell. Do those /have/ to be replaced each time, or can I get by with them as is? If I need to replace them, is there a way to get them at reasonable cost? I looked at a few parts stores online, and the gasket kits ran about half what a running mower on craigslist would cost me.

Another side question... how exact are the torque settings for the head bolts, valve cover bolts, etc as listed in the service manual? I don't have access to a torque wrench. I'm thinking that I can probably get it to within 20% just by feel (210 inch pounds would be 17.5 pounds at the end of my 1 foot wrench, for example) but I don't have a good idea of how exact those have to be for everything to work properly.

Thanks.

 

[chance123]

No need to pull the cam out. Simply remove the valve cover and with the spark plug removed, slowly rotate the engine while observing the 2 rocker arms. Of course you will see them both fully opening and closing, but look for a "slight" movement before or after they fully open or close. That slight movement is your compression release. If on that slight movement, it only moves enough to take up the clearance, Then you either need to adjust your valve lash to the minimum side of the required tolerance.

 

[motoman]

The pros have spoken. Re new gaskets (on my Intek 24 ) the "lubrication" is a mist or fog driven by crankcase pressure so only a teaspoon drains out when the valve cover is removed. Because of that I reuse the existing gaskets by not over torqueing each removal. As long as not torn at bottom I have no problem and have not replaced since major teardown years ago. Take $15 and buy a sears beam type torque wrench. More accurate and long lived than others , though harder to read (and much cheaper).

 

[Anachronomer]

Chance123, I looked at, and felt the pushrods through a good number of complete cycles. I put manual pressure against them to make sure that I'd feel them try to push out at all. They only move during the full openings of the valve. There is no movement before or after on either valve. To be absolutely sure, I readjusted the valve lash on both valves to .004 (the minimum spec) and it still is nearly impossible to pull through the compression stroke.

Motoman, thanks for the tips on the gaskets and the Sears wrench. I balked at the prices at our local big box store, and didn't think to check Sears. I'll have to pick one up.