Troy-Bilt 4 cycle backpack leaf blower has no high rpm

[Richie F]

Bought a TB4BPEC blower off of Facebook market place that looks new.
Starts and idles but that's it.
Came with a new carb (Ebay junk) and same thing.
On the OEM carb drilled out the main jet from .013 to .017 and I can get high rpm but not to spec.
Doing research I see MTD upgraded the carb number. It was #75305676A and now #75308025.
A dealer told me there was a problem with this blower but couldn't remember what it was.
Anybody have any in site to this?
Thanks

 

[StarTech]

First AC4 engine poorly designed engine. Tends to have oiling problems especially when used as string trimmer engine.

I would try adjusting the valves to see if that helps.

 

[Richie F]

First AC4 engine poorly designed engine. Tends to have oiling problems especially when used as string trimmer engine.

I would try adjusting the valves to see if that helps.

Have done that already, they weren't that far off to begin with.
Running at high idle after drill main jet it sounds like ignition is erratic. Has the original plug, going to buy a replacement and test.
I bought this unit for $40 and found another one for $50.
There is a common problem with this engine that I would like to correct.
Seeing that this did run well when new and after X amount of hours it acted up, as others do also, could there be a loss of compression problem?
I'll have to check compression. Wish I had a leak down tester also.

 

[Tiger Small Engine]

Have done that already, they weren't that far off to begin with.
Running at high idle after drill main jet it sounds like ignition is erratic. Has the original plug, going to buy a replacement and test.
I bought this unit for $40 and found another one for $50.
There is a common problem with this engine that I would like to correct.
Seeing that this did run well when new and after X amount of hours it acted up, as others do also, could there be a loss of compression problem?
I'll have to check compression. Wish I had a leak down tester also.

A Troy Bilt 4-stroke backpack blower is a cheaply built unit. I no longer work on Ryobi, Troy Bilt, Craftsman, Poulan, etc. handheld equipment because it is hit or miss with getting it running correctly. Try to find a date of manufacture or ANSI year, that will help with how old unit is. May be down in compression.

 

[StarTech]

Loss of compression is what killing most the AC4 engines here which causing by the oiling issue. I had them to run good cold and then fail hot.

 

[Tiger Small Engine]

Loss of compression is what killing most the AC4 engines here which causing by the oiling issue. I had them to run good cold and then fail hot.

Almost without exception, every piece of handheld equipment (chainsaws, trimmers, blowers, etc. ) I have that are dead, are low/no compression. These are units that customers brought in. Low/no compression can account for 3-5% of equipment I look at. That number will drop considerably next year because I am no longer working on the cheap equipment.

 

[Richie F]

Loss of compression is what killing most the AC4 engines here which causing by the oiling issue. I had them to run good cold and then fail

Loss of compression is what killing most the AC4 engines here which causing by the oiling issue. I had them to run good cold and then fail hot.

I'm confused here. I have a TB4BPEC but you use AC4. Are we talking apples to apples?

 

[Richie F]

Almost without exception, every piece of handheld equipment (chainsaws, trimmers, blowers, etc. ) I have that are dead, are low/no compression. These are units that customers brought in. Low/no compression can account for 3-5% of equipment I look at. That number will drop considerably next year because I am no longer working on the cheap equipment.

This unit isn't dead, it does run.

 

[StarTech]

Yes we talking about the same engine. The engine is just part of the blower.

And just because it runs does not mean it is not worn out. As I said oiling issues these MTD AC3 and AC4 engines is what killing most of them. I cringe everytime one comes into the shop as I know I will likely be wasting my time trying to fix them. One first thing I look for is if a lot is in the air cleaner which is blow-by of the piston rings.

 

[Richie F]

Yes we talking about the same engine. The engine is just part of the blower.

OK so an MTD engine is a AC4. Now if I need parts, like rings, I should ask MTD for part numbers?