TVT691 A couple of problems

[bertsmobile1]

Put your finger on the throttle rod and see if it will hold a constant speed then slowly increase the speed.
Listen to the engine to see if it starves or is running rich.
Also try new spark plugs..
When I do this i Put an inline red spark tester on the plug wire.
This will enable you to see if you are getting a proper spark or not.
Also try saturating the area between the carb & the inlet and see if it sucks the WD 40 into the engine.
You will get speed changes and white smoke if it is sucking .

 

[PTmowerMech]

Put your finger on the throttle rod and see if it will hold a constant speed then slowly increase the speed.
Listen to the engine to see if it starves or is running rich.
Also try new spark plugs..
When I do this i Put an inline red spark tester on the plug wire.
This will enable you to see if you are getting a proper spark or not.
Also try saturating the area between the carb & the inlet and see if it sucks the WD 40 into the engine.
You will get speed changes and white smoke if it is sucking .

It does hold a constant RPM. Although I didn't try it a low rpm. Only mid for a few seconds and increased it a little at a time.
The cheapo temp reader (harbor freight) shows both cylinders are about 400 just out of the head. Not sure the accuracy of the reader, but surely the reader wouldn't be off the same amount on both sides.
IIRC, there are new plugs in it.
That's all I can specifically remember right now. Will check the gaskets, (WD40) tomorrow.

I was told my old small engine guy, years ago, that these carbs have to be set to match each other. I don't see any settings on these carbs. Except the low idle screw.

BTW, could surging come from a slow pulse rate from the fuel pump?

 

[bertsmobile1]

Volume wise the pump can move about 10 times the fuel per minute that the carbs can.

By holding a constant speed I am talking for a bit longer than a few seconds


We have to work out if you have a fuel supply problem, a spark problem or a governor problem.

So you start the mower put your finger on the governor rod to prevent the governor controlling the throttle.
You then hold it at idle for a few MINUTES then gradually increase the throttle till you get to full revs.

If the fuel supply is insufficint then the engine will stall out lean.
If it runs just fine at all speeds then there is a problem with the governor.
If it misses a little then fires & blows a little black smoke then misses again you have a problem with the ignition.

Same story with the spark tester.
If the ehgine is running fine then starts to miss and the flashing is erratic you have a spark problem.

And as for both cylinders being being the same temperatures , if the kill wire or one of the kill switches is faulty and making a ground, the engine will miss on both cylinders.

There are a variety of tests that can be done.
We don't ask you to do them because we like to make you run round like a headless chook.
We ask you to do these things so from the results we can work out what is actually wrong with your engine.

Remember we are here on the end of a computer screen & in my case 1/2 way round the world away.
If I was there drinking your beer I could tell you what is wrong by the way it runs & misses by what it sounds like & smells like.

If you can not be bothered then go play hunches and replace things at random, sooner or latter you will get lucky .