View Full Version : What causes engine surging?

10-03-2009, 01:33 PM
I have a Cub Tank M54 with a Kaw 23 hp engine. The engine started surging yesterday at both low throttle and high throttle. I changed out the fuel filter, no difference. Once i engage the blades it seems to go away. Anyone have any ideas? thanks

DT Lawn Care
10-03-2009, 06:42 PM
I have a Cub Tank M54 with a Kaw 23 hp engine. The engine started surging yesterday at both low throttle and high throttle. I changed out the fuel filter, no difference. Once i engage the blades it seems to go away. Anyone have any ideas? thanks

Clean out your carburetor, or at least try running SeaFoam or other good additive through it, should fix your problem. Also maybe check to make sure your choke butterfly is opening and closing properly, I had a butterfly bust and it was just fluttering around, causing surging and problems. Good Luck

10-03-2009, 09:42 PM
Could be dirty gov linkage, but probably not. Most surging is caused by a lean mixture. In addition to carb problems (before you rip off and dive into the carb) check for a loose carb mount and leaking gaskets. I always check and eliminate the easy stuff first, once in a great while it works.

10-04-2009, 04:24 PM
yea check carb 1st , maybe a spring jumped off, or the idle is set too low.

i did that just last week, set the idle screw too low , and it would surge down and almost die before coming back up

10-05-2009, 03:38 PM
i have a exmark lazer with a 23 kohler. when it surged and then started losing power, the mechanic said it seeded a new carb. I tried to rebuild. $150 later I put on new carb and the problem went away.

03-16-2010, 11:09 PM
Hi all, I'm having a similar issue on a new Briggs Vanguard 9hp motor on my powerwasher. Hoping someone can help me out. I bought it last year and it worked fine for the first 4 or 5 times and then it started acting up. Well,I pulled it out of storage and did the routine maintenance on it. Changed oil, new fuel, replaced oil in the pump, plug, etc... I ran it for a few minutes and seemed to work fine. I decided since it warmed up that I'd wash off our back deck and patio so I went at it. Started right up and I began working. About 3 minutes in once it warmed up it started surging and it eventually died. Had to rechoke it and it would continue to do the same thing. I looked at everything, adjusted what I could and it didn't help. The weird thing is it runs fine at idle but when I throttle up it just bogs and dies. The mixture adjustment has a stop on it so I have limited adjustment. I'm wondering if its something internal? I may just call Briggs since it's under warranty but would rather just fix it myself. Before I tear into pulling the carb any recommendations on other things to check?

03-16-2010, 11:45 PM
Remove the bolt from bottom of the bowl on carb and catch into a small container.(A paint can cap works well,preferably a white one so you can see what comes out).You may have a little water in the bowl causing the surge and eventually stopping the fuel flow and making it die.

03-17-2010, 12:24 AM
Just drained it and it looked like there was no water. There was, however, some very small particulate so there is a chance it may be clogged. I've sprayed it liberally with carb cleaner and will let it sit overnight. I'll hit it again in the am and fire it up. I may just pull it apart and give it a good cleaning. I think there was some residual fuel left in it over winter which means it may be varnished. I'll report back once I give it another go.

03-17-2010, 05:25 AM
Yeah, usually a dirty carb ...
Have to clean all that up real good, inside and out, linkages and all.

Some piece that's broken or worn on the governor linkage.
Still have to clean it if you want to see clearly :p

03-17-2010, 06:39 AM
I can't stand an engine that surges or sputters.

Listening to my neighbor's mower is sheer torture at times. :cry:

People just need to learn how carburetors work and how to clean them.

03-17-2010, 10:21 AM
Most common reason, in my opinion, is dirty Carburetor.

03-17-2010, 03:37 PM
Thanks guys. I gave it another shot, fired it up and the same thing happened. I'll be pulling it later today and see what I find.

03-17-2010, 09:38 PM
It's fixed. So I pulled the carb, disassembled everything I could, cleaned thoroughly with carb cleaner and blew out all the ports and holes that I could with compressed air. It was actually spotless upon inspection but figured there may be some grit in one of the holes. I reassembled everything, fired it up and still had the same issue. At this point I figured it had to be something with the mix. I popped the cap off the stop screw that controls the mixture control and completely removed the pin. Again cleaned and blew out the port and reassembled the screw taking note of how many turns it was seated. Fired it up again and it still did the same thing. I then left it to warm up completely on idle and then began adjusting the mix screw. I closed it almost completely and then started slowing moving it out. I found the point at which it was running better but still surging. I stuck the air filter back on and WALLA it ran perfectly. I made some final fine adjustments and it is now running flawlessly. Come to find out the entire time it was set up incorrectly from the factory. It was about 7 turns off where it should be. I stuck the cap back on and am now good to go. Cleaned my entire deck and patio without issue. Thanks all for the advise.

piston slapper
03-19-2010, 10:32 AM
a common problem that causes engine surging is dirt ingested into air jets. these are usually found in the carb throat behind choke plate. blow thru the jets with carb cleaner.these jets provide the air in the air/fuel mix that runs engine. Partiaaly clogged jets cause the fuel to puddle up causing engine bounce.