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I have a small tiller which has a small wead trimmer engine on it and I replaced fuel filter line and carburetor and when I start it up it idles fine and will accelerate slightly but when I put it on full throttle it bogs down and stalls. When I put on the choke slightly it will run full speed. The engine is the type that has a hole on top so you can use it with a electric starter. thanks

Because you supply us with so little information as to the model of the trimmer and engine, I’m only GUESSING as to what your problem is. Sounds to me like the carb is in need of fuel to get from the idle circuit to the full throttle circuit. Many times this can be resolved by adjusting the carb. As I stated, we don’t know what unit you have, so can’t make a guess as to what carb adjustments are available.

just a guess but sounds like the needle on the carb needs adjustment if it has one, pull the throttle once it warms up a minute or two, and slowly turn the screw counter-clockwise until it runs better. At full throttle adjust it where it runs best. Then let it idle. If it dies adjust the idle faster which can be a stop screw or the cable tension. At idle pull the throttle somewhat quickly to see if it responds well. If it stumbles turn the screw just a tiny bit more counter-clockwise. Do that until it doesn't stumble when you open the throttle. On those engines the temperature outside, how long you use it, how much gas is in the tank, how old the carb or gas is all can affect how that machine will run. I sometimes carry a small screwdriver around when using one of that type engine to tweak it as needed if it doesn't like the day. STAY OUT OF THE WAY OF THE TINES WHEN YOU ARE WORKING ON IT.

We finally found the model number cmxgvamkc29c

I got my opinion of the those throwaway MTD 4 cycle engines. This one is an AC3 version.

It will have a Chinese clone carburetor on it depending the Chinese it may have an adjustment in the center of the rotating barrel. Can be flat blade or micro D tool that is needed.

Also I have seen to be so worn out that they will idle but will not operate at full speed without tweeting the choke.

StarTech said:

I got my opinion of the those throwaway MTD 4 cycle engines. This one is an AC3 version.

It will have a Chinese clone carburetor on it depending the Chinese it may have an adjustment in the center of the rotating barrel. Can be flat blade or micro D tool that is needed.

Also I have seen to be so worn out that they will idle but will not operate at full speed without tweeting the choke.

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We did not see any slot or d slot in the center of the throttle shaft. We even took out a small rubber plug and there was nothing there.

tim4 said:

We did not see any slot or d slot in the center of the throttle shaft. We even took out a small rubber plug and there was nothing there.

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Then it appears to a non adjustable version.

Make sure the gas (and oil mixture if applicable) is fresh and accurate, that the hoses aren't swollen shut that come from the tank and/or replace the carb. The parts manual doesn't show a filter inside the tank but there may be a small one depending on the tank style. Those throwaway carbs can cost from $15 to $50 depending on which brand and whom you buy them from. They aren't all that reliable. Also the hoses swell up sometimes or kink so they might provide enough fuel to idle but not enough to run at rpm. Your carb model is an AC3 / AC3.1 and there does not appear to be an adjustment screw on it other than idle RPM. Also make sure the air filter is clean.

owner manual if craftsman https://www.toolservicenet.com/i/CR...truction_Manual/EN/769-17370_CMXGVAMKC29C.pdf

be aware that MTD shows two different products with that part number, 21AKC29C793 and 21AKC29C791

Jacks 791: https://www.jackssmallengines.com/j...-tillers/2019-models/cmxgvamkc29a-21akc29c791

Jacks 793: https://www.jackssmallengines.com/j...-tillers/2019-models/cmxgvamkc29c-21akc29c793

Both take MTD 75306258A carb

sgkent said:

owner manual if craftsman https://www.toolservicenet.com/i/CR...truction_Manual/EN/769-17370_CMXGVAMKC29C.pdf

be aware that MTD shows two different products with that part number, 21AKC29C793 and 21AKC29C791

Jacks 791: https://www.jackssmallengines.com/j...-tillers/2019-models/cmxgvamkc29a-21akc29c791

Jacks 793: https://www.jackssmallengines.com/j...-tillers/2019-models/cmxgvamkc29c-21akc29c793

Both take MTD 75306258A carb

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Thank you the engine is a 4 stroke and everything is clean and I replaced the fuel line to the filter and new filter.

tim4 said:

Thank you the engine is a 4 stroke and everything is clean and I replaced the fuel line to the filter and new filter.

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I noticed to the left of where the carburetor bolts on there is a round pipe that comes from the engine. What is supposed to go on it thanks.

just a GUESS that is a crankcase vent. Probably goes to the carb or air cleaner.

sgkent said:

just a GUESS that is a crankcase vent. Probably goes to the carb or air cleaner.

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I thought so but can not tell where it hooks up on the air cleaner. There is a small line on the other side that comes from the air cleaner to the engine can't tell where it goes it goes under the covers maybe a fuel vent.

tim4 said:

I thought so but can not tell where it hooks up on the air cleaner. There is a small line on the other side that comes from the air cleaner to the engine can't tell where it goes it goes under the covers maybe a fuel vent.

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The problem was the new carburetor was bad. I bought another new carburetor from ebay

tim4 said:

The problem was the new carburetor was bad. I bought another new carburetor from ebay

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We keep advising people to buy parts from real parts stores and not ebay / amazon for this exact reason
Lots of stuff there that has been rescued from the factory scrap metal bin then sold as "OEM"
SO another case of
"he who buys cheap pays twice "

Thanks for closing the thread and please get your parts from a dealer or one of the genuine on line stand alone specalist small engine parts retailers .
It will save you a lot of time & frustration is nothing else .