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Curtis B.
Curtis B., Technician
Category: Small Engine
Satisfied Customers: 28111
Experience:  have worked on and around most engine models for 35 yrs./Polaris ATV expert
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I have a TVT691 19 HP, twin carb Tecumseh lawn mower engine.

Customer Question

I have a TVT691 19 HP, twin carb Tecumseh lawn mower engine. I bought riding mower that had the engine and mower deck is from another mower. The man was tired of working on it so he sold it to me. It has been a long trip. We got it running but could not control the RPMs. I took it to a lawn mower shop and was told that the governor was shot. We take it apart, clean everything and take pictures and send them to one of your comrads. He said the governor looked fine. We follow directions about adjusting the governor and carbs and get it running but still have RPM control problems. We take it to another lawn mower shop and when he starts the engine, a loud banging noise starts. He immediately kills the engine.
It seems the 2 small screws that hold one of the butterflys on the shaft of one of the carbs came loose and went into one of the cylinders. I was told it was shot. We took it home and tore it apart and found the screws in the cylinder. The cylinder walls were very smooth with no apparent damage. The top of the cylinder was dinged up from pushing the screws up against the head but looked OK. I ordered a new head gasket and installed it. I think we were successful adjusting the valves. When we start it, we can control the RPMs now but it is really smoking. Also where one of the muffler arms go into the manifold (it has a seal around it) it is leaking down on to the muffler. A little smoke is coming off the muffler but the most is coming out of the muffler.
I have a feeling that the carbs are not adjusted right and hopefully causing some of the smoking. It does backfire at times, usually when slowing the throttle down.
Are you ready? Could I be right about the carbs adjustment or the governor causing the smoking and what cab be done about the oil coming out of the manifold?
Submitted: 2 years ago.
Category: Small Engine
Customer: replied 1 year ago.
(Posted by JustAnswer at customer's request) Hello. I would like to request the following Expert Service(s) from you: Live Phone Call. Let me know if you need more information, or send me the service offer(s) so we can proceed.
Expert:  Curtis B. replied 1 year ago.
Welcome to JUST ANSWER small engines, let me try to help you !! Oil out the manifold would have to be from the cylinder! Is this by chance the cylinder that had the screws from the carburetor butterfly? That would be my guess! You didn't remove the piston to check it when you had the head off? Piston may be damaged, and has collapsed the rings on that cylinder. Have you ran a compression test , to see if both cylinders are the same? Carburetor adjustment will only slightly change the fuel. supply, and will have nothing to do with oil in cylinder. I assume that the cylinder with the oil is firing? You ran a cylinder test, by removing one spark plug wire at a time, to see if both cylinders are firing? If engine dies when one wire is removed, the opposite cylinder is not firing. A none firing cylinder could throw out un-burned fuel and oil into the exhaust!
Customer: replied 1 year ago.

I wrote this question on July 11 and I went on vacation on July 15. On the 15th I had not received an answer so I ordered another piston and set of rings. On the 15th I also wrote a question is anyone going to answer my question and was promptly told I would be charged $15 for that question. I appreciate your trying but I don't need any information at this time. May need info when the piston comes in.


Expert:  Curtis B. replied 1 year ago.
OK, let me know. Thanks,