Z335e engine surge

[StarTech]

I got one commercial customer that done worn two choke shafts and one throttle shaft on Kawasaki v-twin with dual barrel Nikki carburetors. These carburetors run around $600 to replace. I have manage to save all three by installing bushings and new shafts. And I also have seen other carburetors too that have the same wear.

 

[bertsmobile1]

In the 5% of places where a fuel stabilizer is actually needed it works very well
In the other 95% it just wastes money and gives the owner a false sense of security
Fuel stabilizers do not stop fuel evaporating from the carb and leaving gum behind and the gum left behind from fuel with goop in it is a lot harder to remove .

 

[Johner]

In the 5% of places where a fuel stabilizer is actually needed it works very well
In the other 95% it just wastes money and gives the owner a false sense of security
Fuel stabilizers do not stop fuel evaporating from the carb and leaving gum behind and the gum left behind from fuel with goop in it is a lot harder to remove .

Right, it does not stop vaporization, from what I read it keeps air from entering the tank that holds moisture from collecting in the alcohol that keeps it from gelling. Can give a 2 year protection. Have worked on generators that haven't run since the storm Sandy 10-12 years ago what a mess, even the Alu. shut off valves deuterate. Do not do much commercial work.

 

[Jonnie_S]

I guess I got lucky by indiscriminately blowing air through the carb. But before doing that, I examined the parts very closely using an assembly microscope (I do electronics design/fab), and saw nothing. If there was something in there, it wasn't in the jets' orifices. Maybe something in the passage between the idle jet and the throttle body??? Anyway, runs perfectly now.

 

[BMS]

B&S 40N877 engine is surging most noticably at idle and low speed, but even at high speed it does not sound right. Sounds a bit rough.
Mower has less than 30 hours on it. 2 years old.
New fuel filter, air filter, spark plugs (old ones looked fine)
Fuel pump seems to work fine. I see fuel trickling into the filter. Crank the engine with the pump output line disconnected and gas spurts out pretty vigorously.
Just for kicks I gravity fed fuel from a container - no difference.
Opened up the carburetor - it looked perfectly clean. Blew out the orifices and re-assembled. This carb has a single emulsion tube, not the 2-tube version I've seen in several youtube videos.
Governor linkage and springs all good.
Fresh fuel (although it is 10% ethanol).

Read lots of posts here and in other forums about engine surging and I'm running out of things to check.
The mower runs ok at high speed and is perfectly usable, but just doesn't sound like its running smoothly. At its lowest speed it lopes badly, almost stalls.
Its still under warranty but a hassle to bring it to a JD service center. Plus, if they determine it just needed a "tune-up", i.e. normal maintenance, that's not covered.

Any ideas?

-Jon Usually when they surge, it could be a plugged passage in the carb, Soaking or sonic cleaning works the best, you did not post the Type or code number from the engine, most of those 40 cubic inch engines have a Nikki carb on them, If the static timing of the governor is correct, it usually will be the carb that is the problem making them surge and run rough, and yes, they had their share of problems with those Nikki carbs, those O-rings can be a real problem, B&S only warranties the carbs from 90 days of DOP. Make sure your intake gaskets are good, they use either a red square O-ring or a gasket. The approx. price on those carbs is 212$, Without the Type and code i cannot tell you the correct carb P/N. Just so you know, I have been a B&S dealer for 50 years. Plus, if i remember right, there is no carb Rebuild kits for them, {Nikki} all parts are sold individually. I Hope this helps; My Business E-mail is stanbms@msn.com

 

[hlw49]

I got one commercial customer that done worn two choke shafts and one throttle shaft on Kawasaki v-twin with dual barrel Nikki carburetors. These carburetors run around $600 to replace. I have manage to save all three by installing bushings and new shafts. And I also have seen other carburetors too that have the same wear.

Yes that seems to be a problem with the larger Kawasaki engines. They vibrate too much. Had one do that wore the housing out. Luckily we had a junk engine with a good carb on it.