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Curtis B.
Curtis B., Technician
Category: Small Engine
Satisfied Customers: 26054
Experience:  have worked on and around most engine models for 35 yrs./Polaris ATV expert
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I have a craftsman 9 HP snow blower. It has a Tecumsehmotor

Customer Question

I have a craftsman 9 HP snow blower. It has a Tecumseh###-##-####motor on it. I had the carb rebuilt at a local small engine shop but when I started it up it "loaped" for a bit and then started spurting/back firing intermittently. There was also a glow in the muffler with the occasional spark.
JA: Thanks. Can you give me any more details about your issue?
Customer: Like what I thought I explained it pretty clearly.
JA: OK got it. Last thing — Technicians generally expect a deposit of about $18 to help with your type of question (you only pay if satisfied). Now I'm going to take you to a page to place a secure deposit with JustAnswer. Don't worry, this chat is saved. After that, we will finish helping you.
Submitted: 9 months ago.
Category: Small Engine
Customer: replied 9 months ago.
I bought this snow blower second hand. I put the throttle linkages back into the holes they came from but I cant speak for the previous owner. The blower runs and operates but is not idling right. The sputtering/back firing is still present.
Customer: replied 9 months ago.
I tried taking a video but it will not upload. The blower will even rock a bit due to its uneven idle. The shop that repaired the carb has a good reputation and from all I could gather does good work.
Expert:  Curtis B. replied 9 months ago.

Carburetor is a none adjustable model. Only adjustment is idle speed. The needle valve and float, control the fuel flow into the bowl.

Expert:  Curtis B. replied 9 months ago.

With this engine, you may have a valve sticking or that needs to have some clearance. Problem with that, is the valves have to be removed from the block and ground off to add clearance.

Customer: replied 9 months ago.
I may have a valve sticking.
Expert:  Curtis B. replied 9 months ago.

You can check valve clearance by removing the valve cover, that the vent hose comes off of, and see if valves are too tight. .006 will be good. Zero causes problems.

Expert:  Curtis B. replied 9 months ago.

Service manual.

Customer: replied 9 months ago.
I have already found this online. I will look into it here and be back with you in a minute.
Expert:  Curtis B. replied 9 months ago.

OK>

Customer: replied 9 months ago.
Can you be more specific concerning the valve cover please
Customer: replied 9 months ago.
I looked through the manual before this conversation and just now and still have not seen a diagram/any other information that applies directly to what im after
Expert:  Curtis B. replied 9 months ago.

Engine breather page 87, is where you remove and check valve stem and springs for clearance between valve stem and lifter.

Customer: replied 9 months ago.
ok thanks i will look into that quick here
Expert:  Curtis B. replied 9 months ago.

OK>

Customer: replied 9 months ago.
basically I'm going to have to take apart the whole motor to see if the valve may by flush or may not in which case I would be back at square one?
Expert:  Curtis B. replied 9 months ago.

You can check them, but not adjustment them without disassembly!

Customer: replied 9 months ago.
I have a side mounted breather. Such as in Figure 49 on page 87 but after taking it apart I still dont understand how this helps me. I dont see any valve such as in the other diagram.
Expert:  Curtis B. replied 9 months ago.

#172 is the cover shown for your engine, the cover and baffle have to be removed, and you should them see the valves and springs and lifters

Customer: replied 9 months ago.
172 is a cover but after you take it off your looking at a filter. I removed parts 173 174 172 169 171 and 170. Hear is a pic of what I saw.
Expert:  Curtis B. replied 9 months ago.

Take it off, go deeper!

Customer: replied 9 months ago.
ok i will be back in a minute
Expert:  Curtis B. replied 9 months ago.

OK>

Customer: replied 9 months ago.
Here is what I see
Expert:  Curtis B. replied 9 months ago.

Thats it. The valve stems and the lifters, You want to measure the gap between stem and lifter. Use feeler gage and see if you can slip at least .004 between the two parts, you will have to turn engine until the valves are closed,

Customer: replied 9 months ago.
I dont have a feeler gage. perhaps I can get one tomorrow?
How do I turn the engine with that sort of accuracy?
And you know when they are closed because they are in the lowest position they can be?
Expert:  Curtis B. replied 9 months ago.

Accuracy is not that close. You can turn engine and hold gage against the two parts, if there is clearance ,the gage will slip through when valve reaches its lowest point. As long as it has clearance it should work, and not cause the misfire. Zero is when it causes the problem/

Customer: replied 9 months ago.
Im sorry and maybe im being dense but I still dont fully understand where exactly Im supposed to be measuring.
Customer: replied 9 months ago.
or with what. I dont have a feeler gauge
Expert:  Curtis B. replied 9 months ago.

Here is basic valve setup. Your lifter is not a rocker, but a rod pushed by the camshaft, but it should give you idea where you check the gap.

Expert:  Curtis B. replied 9 months ago.

Here is Utube video.

Customer: replied 9 months ago.
if I can get a feeler I can check that.
If it does not have clearance than I need to take the head off. Remove the stem and grind it down a bit.
What if it does have clearance?
Customer: replied 9 months ago.
I will have access to a feeler gauge tomorrow.
Expert:  Curtis B. replied 9 months ago.

You can still have valve problem, valves may not be seating, and would need to be reseated.

Expert:  Curtis B. replied 9 months ago.

I will be here tomorrow , most of the day. Let me know what you find with clearance.

Customer: replied 9 months ago.
ok how do I contact you? I have not used this before.
Expert:  Curtis B. replied 9 months ago.

There will be a link in your Email to get back.

Customer: replied 9 months ago.
ok cool.
Expert:  Curtis B. replied 9 months ago.

Good night!

Customer: replied 9 months ago.
Ok so here are some pics of when the stems are up. Even when the stems are up there is no gap. they travel through the bottom.
Also I removed the belt cover to be able to turn the shaft easier and I noticed that at a certain point it became very hard to rotate. There was a good deal of resistance. It will of course make the full rotation.
Expert:  Curtis B. replied 9 months ago.

Only time there would be a gap is when the valves are all the way down. When you were turning engine, did you have spark plug removed? If not you were feeling the compression. But with no gap, the valves need to be (adjusted).

Customer: replied 9 months ago.
I watched the youtube video 3 more times and the best I can see is that the stems in the video stops before the bottom of the box. He slides the feeler gauge between the bottom of the box and the bottom of the stem to get the measurement. However in my case as shown in the pictures, the stem goes through the bottom of the box. I took the picture while the stems are up to illustrate this. Or am I missing something?
Customer: replied 9 months ago.
Its also my understanding that I could also take the engine apart and see if the stems rotate. If one or both of them do then I would know that they are sitting against the bottom and need to be ground down. Right?
Expert:  Curtis B. replied 9 months ago.

The bottom part of the (stem) is the lifter, the upper part is the valve, you have to measure the distance between them, Take a screw driver and lift up on the valve spring to see the gap. Then you will know where the measurement is made, between the two parts!

Customer: replied 9 months ago.
OK I think I have a bead on it now. When the lifter presses up of coarse there would be no gap. Im going to go get the gauge and check it.
Expert:  Curtis B. replied 9 months ago.

Correct!

Customer: replied 9 months ago.
One of the things that confused me is that in the youtube video the lifters are flush with the bottom but with mine they are elevated. I found the separation point and will be proceeding to the store shortly to get a gauge. My gut reaction is that they are flush but I cant be sure till I get the gauge. If that is the case then I have to pull it apart, get the head off, get a spring puller and remove the springs to remove the valves and then grind them down a tiny bit. Presuming that this will be the outcome how would you advise I grind them down?
Customer: replied 9 months ago.
Do you think I will need to replace any gaskets after the disassembly? Such as for the head?
Customer: replied 9 months ago.
Or are they usually reusable if you are careful?
Customer: replied 9 months ago.
I got the feeler gauge and could not get even the smallest between them. As per my previous questions, how do you think I should go about grinding down the valves?
Customer: replied 9 months ago.
I tore down the motor. After seeing the piston and placing it at the top I still could not get the .008 gauge between the two. However the two valves do not turn when closed like in the youtube video. They appear to be flush on top and only are able to be turned when up. I would assume that the valves still need to be removed and ground down?
Expert:  Curtis B. replied 9 months ago.

Yes, until you can get the proper clearance, Do NOT take but a slight amount at a time, and while valves are out, reseat the valves in the block.

Customer: replied 9 months ago.
I have been doing research and I do not have the capacity to grind them down with the accuracy and fine finish that I have found it will require to work properly. I would need a machine shop to do the job right from what I have been reading. I noticed that when asked you did not have any instruction as to how to grind them down only that they needed it. This forum would appear to be geared toward the novice which in my opinion is really not equipped for that sort of modification. It is my feeling that my $18 would have been better spent if you had simply outlined the whole of the process, giving me the opportunity to see the pitfall and just take it to a shop before taring it down to asses a problem I was ill suited to fix. That being said I have found your patients to be good albeit fruitless. I am either going to take it to a shop in pieces and see if they would like to finish it with their compliment of tools or pass it off for parts or repair in a auction or something. This is the end of the project for me. next time I will just spend more and take the rest of the day off. I would have gladly paid $18 for someone to tell me not to attempt this and saved me half a day, which I think would have been well worth it.
Expert:  Curtis B. replied 9 months ago.

I sent the service manual. That is all the help that you should need to get the basic points. You can grind the valve tips with a sharping stone or a good file, they don't have to be perfect.

Expert:  Curtis B. replied 9 months ago.

I work out in the country and always try t figure out how to do it , without having to go to town! Like i'm stuck in the desert and have to get home! Good luck with it! Thanks,

Expert:  Curtis B. replied 9 months ago.

Please accept to close!