MTD Powermore 679 CC V-Twin only runs on one cylinder

[semimechanicman]

I got a basically free Troy Bilt super Bronco with 50 inch deck and it starts but needs throttle cable replaced, it has a crappy Chinese mtd engine.

Apart from that, it only runs on one cylinder, I noticed it since it would run very poorly with blades engaged and bogged down a lot.

Both sides have very good spark and I can see the cylinder move up and down.

I cleaned the carb and this was done in an hour in a Friday afternoon (today) but I touched both sides with my hand after running for 10 seconds and one side was cold and the other getting hot.

I didn’t have any time to see any problems and don’t have much information but I just want to have some ideas in mind. Anything would be appreciated thanks.

 

[ILENGINE]

Have you removed the valve cover and checked to make sure the push rods are in place and the valves are working correctly..

It always cracks me up when people complain about the MTD engine and then go buy an engine made by the same company but sold under a different name and then claim it is the best engine they have ever owned.

 

[StarTech]

IL, would you happen to have the PN (form number) for the 8Q engine service manual? Looking to add it to my manual collection as I probably run into one these V twins in the future. So far I have anything other the single MTD OHV engines.

 

[ILENGINE]

IL, would you happen to have the PN (form number) for the 8Q engine service manual? Looking to add it to my manual collection as I probably run into one these V twins in the future. So far I have anything other the single MTD OHV engines.

Don't see any listed as an 8Q but there is a manual for the Q78 series which is form number 769-15992

 

[semimechanicman]

Have you removed the valve cover and checked to make sure the push rods are in place and the valves are working correctly..

It always cracks me up when people complain about the MTD engine and then go buy an engine made by the same company but sold under a different name and then claim it is the best engine they have ever owned.

Havent had time to work on it as I discovered only one cylinder was working yesterday at 9 pm at night And had to go. Now im remembering that that carb has two jets and maybe one is still clogged or something, and yea I know it was kind of a mistake to buy a chinese engine but at least it wqs only $100

 

[Born2Mow]

Check the Big 3: Fire, Compression, Fuel.

You already check Fire.

 

[StarTech]

Don't see any listed as an 8Q but there is a manual for the Q78 series which is form number 769-15992

oh forgot the naming pattern. the engine here was a MTD 8Q78XUA which makes it Q78. Off looking for a downloadable PDF version of the 769-15992.

 

[semimechanicman]

Check the Big 3: Fire, Compression, Fuel.

You already check Fire.

Yes I am hoping it is the jet that is clogged because that carb has two jets one for each cylinder. Or the valves need adjustment

 

[Born2Mow]

Yes I am hoping it is the jet that is clogged because that carb has two jets one for each cylinder. Or the valves need adjustment

1. Take out both plugs. Tightly hold your thumb over the plug holes 1 at a time. Hit the electric start momentarily. If a blast of air blows your thumb off the plug hole, then it ain't the valves.

This is not to say your valves don't need to be adjusted, just that the valves are not your issue.

2. So, what might have happened to clog the carb jets ? Did the PO store the mower all winter with fuel in it ? Some of this you need to ask the PO. Why ask and answer a 1000 questions online, when 1 quick phone call will suffice ?