Surging engine?

[wheeler]

23hp Briggs, Surges on throttle up, have to pump the throttle to get it to go. Idles fine sometimes. Ideas for where I need to start looking ie.fuel pump, plugs, carb adjustments? Yes, probably all of them but what is the most common thing to cause this issue? This motor is less than a year old.

[beagle man]

Sounds like water in your gas, might try dry gas(red stuff) or sea foam.

[wheeler]

I forgot to add that I have been putting sea foam in the gas. Makes no difference.

[rcn11thacr]

My 27 hp kawasaki did the same thing some time back and the same thing half the day yesterday. It would die and id have to choke it to get it to crank back up, hold the choke in for a minute or two while im driving until it settled down, then it does it again. Frustrating. I've pulled the carb completely apart, cleaned it all up and it ran fine for 20-30 hours, then it started doing it again recently. Using hi test and sea foam didnt really make much difference. i am inclined to think its ethanol in the fuel causing this problem. I'm going to get some non-ethanol fuel and give it a try. I'll report back if it changes things for the better.

[wheeler]

rcn11thacr

Interesting. I'd be interested to know if it works please let me know. I wonder why when you pulled the carb and cleaned it, it ran well for awhile after that. Hmmm, interesting.

[rcn11thacr]

When i pulled the carb, there was no "obvious" problem. A small amount of build up here and there, as to be expected but no smoking gun. I could guess at it and say this or that, but if i did then id be doing that "just guessing". Since i know the fuel line is good, it has a new fuel filter, the fuel was new, its been running fine so there isnt any reason to suspect an adjustment issue on the carb, and when i pulled the carb apart it was clean and all of the internals were in good condition, i'm left with a very short list of options. The plugs were also just changed last month and i gapped them correctly, and the fuel pump runs strong. So that leads me to the opinion that the crappy rubber and gasket eating ethanol fuel is to blame. I could be off the mark here but i cant think of anything else thats not been already covered during my diagnostic review. If i missed something, feel free to recomend it...

[wheeler]

Well, actually I'm in the same boat (aka six wheeler) here. I really don't think I need to pull the carb yet as there are many other smaller options and the engine is less then a year old. I agree a good start and probably a simple start is to go with the non-eth fuel and see what happens. I'm just curious why after pulling the carb and cleaning it, it ran fine for 20 to 30 hours? I don't believe that any ethanol fuel caused any gunk issues in short, but it seems to me that there might of been a possible air leak where you tightened the carb to the manifold. Just a thought but you might want to check or tighten the carb bolts again. It be interesting to have it running and start to tighten the bolts as it idles to see if it improves it's idling speed. Just throwing things out there for us to look into.

[rcn11thacr]

I'm just curious why after pulling the carb and cleaning it, it ran fine for 20 to 30 hours? I don't believe that any ethanol fuel caused any gunk issues

There are so many complaints about ethanol fuel used in these type motors, be it mower, saw, etc... This is by no means a new idea (or fact for that matter), it is well known that ethanol fuel eats rubber and gasket material for breakfast. A quick google search will show you so many stories that you will get tired of reading, or just ask any local mechanic... When the gaskets and rubber material break down they turn into tiny little soft pieces that clog up all of the spots in a carb or efi setup. The disintegrating parts done disappear, they got to go somewhere.

[wheeler]

I'm going to get Non-ethanol fuel myself and try it out. I will let you know what my machine does when it runs on it.