Tuff Acting Up

[StainlessDeal 16]

My little Tuff 4gpm 11horse (Honda GX 340) decided to quit on me today. It has had a history of running rich and fouling out, so I went with a slightly hotter plug but never leaned the mixture because the problem seemed restricted to low pressure (X-jet and large orifice) running, and after the new plug was much less of a problem.

Anyway today was supposed to be in the 40's, so I was finishing some truck washes at a regular flatwork customer's place. The weather was socked-in freezing fog, and I was running 145 degree water and hurrying just to beat the freeze. Three-quarters through a trailer, the unit starts popping a backfire about once a minute, on the third one or so I let off the trigger to hear better. I could tell the power was down, but she revs back up. I decided to check the fuel, and shut down. I had lowish fuel, so I filled and when restarted, it would run until I pulled the trigger.

I pulled the plug (fouled), and cleaned her up. Same lack of function. Pulled it again, was a little sooty, so I recleaned and checked fuel flow and air cleaner. The air filter was pretty badly oiled up, so I tried her without, and she ran as if the choke were stuck.

What am I not thinking of? I'm planning on talking to the local guys tomorrow, but I don't want to be blindsided. This is a very low hours unit maintained correctly with good clean oil.

What do you think?

__________________

[Russ Johnson 141]

Is it smoking black? That engine has a fixed jet so mixture can't be adjusted (short of changing the jet). How long did you run it with the dirty air filter? How does the compression feel? If you ran it a long time with a clogged air filter, and your engine is equipped with a spark arrestor on the muffler, there's a possibility of the exhaust being clogged with soot. Might just need a valve adjustment, too.

[StainlessDeal 16]

I'm not proud to say this, but I'm not sure how long the filter has been dirty. When I received this machine the freight outfit had knocked it over, and it had oiled itself up pretty well. I cleaned her up and billed the carrier for my time and trouble.

I had at first assumed that the smoke and odd mixture characteristics were because of an oiled exhaust system and maybe intake lower side, but today she was blowing a raft of soot at the end. It hadn't occured to me that the carb and air cleaner were as likely to be oiled up. I'm positive that the exhaust is sooty.

Thanks for the heads up on the carb, a friend suggested changing the plug that seemed to work (he's a small engine guy at a Deere dealer) so I never checked for a way to lean her out. Now I'll know in the future.

I'll see about the valve adjustment, it wasn't running well enough to say, and I didn't put a guage on it to check the compression, but it sounded poorly timed , if you follow me. I wouldn't doubt that a valve adjustment is due.

Thanks again Russ!:)

[Russ Johnson 141]

.006" intake

.008" exhaust.

[StainlessDeal 16]

You are too helpful, Russ. Thanks. I'll let you know how it goes.:)

[StainlessDeal 16]

On another site, somebody was asking how to go about cleaning the exhaust out, I wound up not having time to go after this work myself, and handed it off to a local Honda Industrial engines dealer and service center.

If you were going to clean out a sooty exhaust, would you disassemble it and blow out with compressed air, and then go from there, or would you do it another way?

I'm embarrassed to say that I didn't ask the service guys how they planned to go about it.

[Russ Johnson 141]

The only thing that would clog is the spark arrestor, the screen thing on the muffler. Removing it, loosening the soot with a brush, and blowing it out with compressed air is all that is needed.

[StainlessDeal 16]

Thanks Russ, I wasn't sure if there could be a buildup inside. Thanks for the information, and for being so quick to answer.:)