Lawn Care Forum banner
Cancel
Create thread New Forums

10.5 HP engine is surging

1 reading
Jump to Latest
1 - 20 of 34 Posts
T

THC

· Banned
Joined
·
2,153 Posts
Discussion starter · #1 ·
This is not the same snow blower as in my other thread here. This snowblower was surging last season but would come out of it, I assumed it was warming up or something. But it's NOT cold today and I started it again and it surges badly. I have to leave the choke mostly on and I can't power down the throttle without it stalling out.

I googled and it said gummy card, govenor (whatever that is), and/or it's running too lean.


Any suggestion what I should do to this machine? It's fairly new and it very good shape.
 
#2 ·
try adjusting the mixture needles on the carb if it has them, otherwise you will (and probably should) take it off and dunk it, use fine wire and poke all the passages in the carb body and (if it has a bowl) the brass nut if it has any holes.
 
#3 ·
Has it been stored with Gasoline in it, if so, your Carburetor is gummed up and the small passages inside are not letting fuel flow freely. The Carb needs to be taken apart and cleaned Good With Carburetor/Choke cleaner. That it runs better with the choke on, indicates that you are cutting down the air to better match the amount of fuel that can get through, So you probably have a build up of Varnish (which is what old gas turns to) in your Carb, restricting the flow of Gas.
 
#5 ·
THC said:
I can take the carb off tomorrow, I don't need a kit or anything do I? Gaskets or whatever?

(It was stored with gas btw)
Click to expand...
OK the chances are that the gas turned to varnish, if you are carful with the gaskets you should be OK You have to take the Carb apart. Get a spray can of "Carburetor/Choke cleaner, not Gunk or degreaser, you need solvent!! Spry through all the jets and ports. When you go to take out thbe needle valves, first screw them in gently till they bottom out, count the turns and make a note of it. So when you put them back in you can set them at the same spot, Do you understand what i mean? You may have to adjust them a bit once it's all put backi togeather.
 
#6 ·
I've worked on many of these carbs over the years, and usually they are the snowblower carbs that get gummed up from the months of sitting idle. So, like the other guys said, remove the carb and disassemble and try to clean the passages with Carb cleaner. If that doesn't work, I've had to soak the carb overnight in carb cooking solution. This will remove all varnish, rubber, plastic and everything, so be careful. I've been told that in one of the passages, there is a little ball that is supposed to float freely, and when that gets gummed up, fuel cannot flow correctly, especially at lower speeds. As you re-assemble the carb, if you didn't count the jet settings, you can turn them in until they barely seat, and back them out 1.5 turns and the engine will usually start and a little fine tuning will get it to purrr like a kitten.

Once you get it running good, be sure to run the carb out of gas in the spring, to prevent this in the future.

Hope this helps and Good luck!
 
#7 ·
I agree with everyone else, before you pull it apart you might drain most of the fuel and pour in some fuel injector/carb cleaner into the fuel and run it and see if that takes care of it....... like a 1/8th of a tank of fuel and a can of injector/carb cleaner.... it not then pull it and clean it.
 
Discussion starter · #9 ·
Same problem. I took the carb apart and it was shiney like brand new. I cleaned what I could, a couple parts I couldn't get out like the main needle seat and the centre piece. But they wer'nt blocked. Sea foam seemed to run through it easy. I cleaned the jet screw etc. And like I said, everything looked brand new.

When I put it on, same surging problem. I tried adjusting the speed idle screw, that was the one always moving when the engine surged. After a while I was able to turn choked off but I could not adjust the speed at all with the throttle. Plus when the choke would be mostly on it seemed to idle way too fast.

Lots of gas comes out of the gas line.. there was a very small burr or wearing mark on the needle. Float was good, bowl was clean as new.

What should I do? rebuild kit and the tools to get out those needle seats and that centre piece or take it to a shop?
 
#10 ·
It would be most helpful to know the make and model #'s on this engine. It could be as simple as the retaining nut in the bottom of the bowl has a blocked passage if so equipped but that depends on make and model of engine. please send info so we can help. Thanks.
 
#12 ·
Either turn off fuel or pinch off gas line and remove the brass retainer bolt under bowl. Look carefully at the retaining bolt and see if there isn't a tiny hole in the outer edge if the shank of retainer . You may need to run a small wire thru it and also clean any debris from the hollow portion of the retaining bolt. If this carb is so equipped these ports are where the fuel is p/u by the main jet.
 
Discussion starter · #13 ·
FIXDISS said:
Either turn off fuel or pinch off gas line and remove the brass retainer bolt under bowl. Look carefully at the retaining bolt and see if there isn't a tiny hole in the outer edge if the shank of retainer . You may need to run a small wire thru it and also clean any debris from the hollow portion of the retaining bolt. If this carb is so equipped these ports are where the fuel is p/u by the main jet.
Click to expand...
That bolt had a small bearing it the very bottom, I couldn't tell if that was plugged or not. I was trying to use compressed air but it was too small for me to see anything. The other holes were on the threaded part of the bolt. There was two larger holes at the bottom, across from each other and a very small one farther up. They werent' dirty at all but I still stuck a wire from a wire brush through them.

There was also another jet bolt along the side of the carb, it was clean also.
 
#14 ·
Ok, this opens up a whole new can-o-worms. If this is an electric start and it has a shut down solenoid on the bottom of the bowl then the solenoid itself could be sticking in closed position or not opening fully. Have you checked operation of this fuel shut-off soleniod ?
 
Discussion starter · #15 ·
I never saw anything at the bottom of the bowl that is electronic. Just the brass jet bolt, the bowl itself, the plastic float, the needle. I took of the entire carb and brought it inside the house, no wire at all, just a linkage to the govenor.

The only wire I touched was on the outer housing, where you insert the plastic key. But that was fine. It does have an electric start though.
 
Discussion starter · #17 ·
FIXDISS said:
Still need make and model to get a diagram. Did you look at that bolt from bottom of bowl and inspect it for clog in the passages ?
Click to expand...
I found my manual it has a spot where I should have wrote the make and model number and even a picture of where it is. LOL, I'll get it tomorrow, its 11PM.

I have been reading up and it seems that I have one of those non-adjustable carbs.

Thanks for the help, I'll cya tomorrow.
 
#19 · (Edited)
Oh, Briggs, I just remembered...

The MODEL number on Briggs engines is stamped on the side of the aluminum valve cover!
It's not in the manual, it's not on that little square sticker either, and you might have to
remove it to get to that, not sure but it's on the valve cover itself.
Ultimately we have to have that model number, whether for this or subsequent repairs,
sooner or later you need this POS number so get it lol, oh and write it down too.

Also they are notorious for having bowl / float / jet blockages, at least one of mine did.

It really sounds like an air leak, that's what causes surging, the fact that you're having to partly choke it
backs this up, I say it's either that or a fuel shortage.

The gasket between carburetor and engine, I'd inspect this real good and if in doubt at all, replace it.
Completely and carefully remove the bowl and pull all that apart and clean it all out real good, careful there are
several tiny parts don't let them get lost, the jet leading out of the bowl into the carb needs to be cleaned as well.

And again that dang PCV rubber tube, if it is at all cracked or corroded it needs replacing,
inspect this tube while getting the model number, it's that black rubber tube that goes from
the valve cover to the air cleaner / carburetor assembly.
Can't say that would cause surging per se but I can attest if this tube leaks it WILL make it run all sorts of crappy.
 
1 - 20 of 34 Posts
About this Discussion
33 Replies
11 Participants
Last post:
ProcsLC
Lawn Care Forum
posts
7.2M
members
230K
Since
1999
A forum community dedicated to lawn care and landscaping professionals and enthusiasts. Come join the discussion about performance, modifications, classifieds, troubleshooting, maintenance, and more!
Full Forum Listing
Explore Our Forums
Lawn Mowing Pesticide & Herbicide Application 🔧 Mechanic and Repair Business Operations Lawn Mowing Equipment