# Craftsman to Tecumseh conversion



## butchf

Does anyone know how to convert 143.019003 Craftsman engine model to the proper Tecumseh model number?

The engine is on a 26", 2 stage, electric start, 9 HP snow blower,
Craftsman model number 536.886260, serial number 830618419.

I looked in the Tecumseh L-head manual, but it starts with 143.2xxxxx.
So I'm guessing it must be a different style engine.
Thanks for any help!


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## Shryp

143.019003 hmsk90-156536d


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## butchf

guess I should do a better search before I post....
I found the conversion here, http://sears.pammar.net/tcross.pdf.:D
Turns out to be a HMSK90-156536D.
I found it on My Tractor forum site.....thx so much!


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## butchf

hey Shryp, have you ever tried to adjust the governor on one of those?
I'm having a real problem getting it to idle and run smooth at high speed.
If I smooth out high speed it won't idle???
It has a "fixed adjustment" carb. I can raise the RPM from the throttle control screw and there is a idle adjust screw but no idle mixture or high speed adjustment. The only other change I can make is the governor linkage.
It goes to the throttle on the carb and throttle control lever.


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## Shryp

No. Did you try cleaning the carb?


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## butchf

Yes, I think I may have to adjust the float as it calls for 11/64 gap and this one is about .090 bigger.


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## butchf

Would a bad primer tube cause this surging issue?


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## Shryp

I have heard bad primer circuits can create air leaks. Not sure myself, but sounds logical.


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## butchf

Thanks for the fast reply!
After working on 250+ machines, this is the first one that is driving me nuts.
When I figure it out I'll post up for all to benefit.

Got to go move the shop this morning......about 3000 sq ft bigger building...

got delivery's to do at 10am and lumber coming in at noon....

catch you later


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## BOSMECH

I hope this helps.
http://www.cpdonline.com/692509.pdf

Also make sure that the linkage is clean and that it is all in the right holes.
I am sure you have checked all that though from your experience.
The govenor adjustment is very easy though.


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## BOSMECH

*ENGINE SURGING​*1. Try to stabilize the engine R.P.M. by holding steady the solid link between the governor arm and the carburetor
throttle, using a pliers or fingers.
2. If the engine R.P.M. stabilizes, the governor or governor adjustment should be checked. See "Service" governor
adjustment procedure in this chapter. If the engine R.P.M. does not stabilize, the engine will require additional
checks, see Chapter 9 under "Troubleshooting".
3. If the problem persists after the governor adjustment, check the engine R.P.M. found on microfiche card # 30. The
R.P.M. settings are critical. If the R.P.M. setting for high and low speed are within specification and a slight surge
is experienced, increasing the engine idle R.P.M. setting slightly may eliminate this condition.
4. Check the governor shaft or linkages for binding, wear, or improper hookup. Check the governor spring for adequate​tension. Repair or replace as necessary


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## butchf

*thx*

Bosmech.....
I followed those instructions....problem being, in the manual they do not discuss the gov adjustment for this style......strange
I watched a guy on youtube(donyxxxx) making the change though.....
Problem I'm having is that when I go to increase the RPM it over revs and a very small rotation of the arm to slow it down does not allow full throttle.
I was careful to mark the factory setting and returned to factory. I then tried to use the throttle lever setting screw to raise RPM slightly. I could get it to smooth out a little, but then it spits fire out of the exhaust, sputters a bit out of the carb, and will not idle down.
From all of the changes and cleaning I've done, it appears that I'm not getting proper fuel flow into the carb. 
If I get a chance today, I'm going to adjust the float per the manual you referenced. 11/64 gap to the base of the carb.

Thanks very much for your reply!

When I cleaned the carb I did a pop-off test with the needle valve and I was good. But just to be sure I think I'll just do a full carb rebuild, flush the fuel system, and check the primer system.
I was trying to avoid all this because I'm not getting paid for this machine.


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## BOSMECH

Have you taken the case cover off and checked the govener inside.
I had to replace one on my 6hp tecumseh one time now that I think about it for kinda of the same problem. 
It was very easy to do just need a case cover gasket.


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## smallengineguy

TGhe engine surges at high speed because it's leaning out. If you have had the bottom bolt out of the carb and all holes are clean, then it's that brass screw on the side of the carb with the plastic cover on it. Remove that screw and blow compressed air into the hole (I do it with it running and the engine eventually stalls) It may take 2 or 3 tries, but that usually does it.


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## butchf

smallengineguy said:


> TGhe engine surges at high speed because it's leaning out. If you have had the bottom bolt out of the carb and all holes are clean, then it's that brass screw on the side of the carb with the plastic cover on it. Remove that screw and blow compressed air into the hole (I do it with it running and the engine eventually stalls) It may take 2 or 3 tries, but that usually does it.


Funny....that does not exist on this carb.


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## butchf

*update to the saga*

I took off the muffler today expecting to see a poorly fitted gasket. I had a Toro last year with with that problem and the dealer couldn't find the problem.
Go figure, there was not any gasket and evidence of a very rich running machine. The muffler bolts are tabbed from the factory and these had never been removed since it was new.
I got a new gasket and installed with hopes of solving this puzzle. It didn't make any noticeable difference.
I guess I'm back to the carb again.


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## butchf

smallengineguy said:


> TGhe engine surges at high speed because it's leaning out. If you have had the bottom bolt out of the carb and all holes are clean, then it's that brass screw on the side of the carb with the plastic cover on it. Remove that screw and blow compressed air into the hole (I do it with it running and the engine eventually stalls) It may take 2 or 3 tries, but that usually does it.


Dang, I found it. When I removed the cap there was a "fixed jet " style screw. I removed the screw, cleaned, and re-installed. No joy there.
So I proceeded to play with it while running the machine. I could dial in a setting that solved the problems but the screw would not stay in place. 
I took 3 orings from another carb project and put them on the screw creating a seal and tension to hold in a fixed position. Similar to the spring setups. I'll most likely get some thread sealer to replace the oring setup at a later date. I found that if this screw was backed off from full in by as little as 1/8 turn, the machine would respond to all other adjustments perfectly.
I had to re-adjust the throttle lever high speed adjustment and the idle speed by backing them both off a bit.
It now starts easily, idles down, and stopped all surging. The transition from idle to full throttle is excellent. A simulated load test went good as well. Now I need some real snow to verify the operation under load.

Thanks for your input! I never would have played with it, had you not posted.


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## BOSMECH

Instead of thread sealer could you put a spring in there like on my carb and others like you mentioned.


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## butchf

BOSMECH said:


> Instead of thread sealer could you put a spring in there like on my carb and others like you mentioned.


Yeah, that would be the best way. The problem is that this screw head does not have enough of a shoulder.


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## BOSMECH

Put a small washer under the head then.


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