Repairs duraforce carb when to rebuild?

[beg]

I have a 10550 and a 10323 both with the plastic carb.I have seen all the youtube videos where this works and that works but my opinion is that the carb body warps and no drilling jets or spring replacing is going to cure that.also after the gaskets have been r and r'ed several times they too will leak air as will the warped carb body causing the surging issue so many refer too with the duraforce engine.I rebuilt the 10550 carb and it runs great but 55.00 is 55.00 bucks. now on the 10323 same thing but it has to run right?you would not think that just one little spring will make it surge and run erracticly all by itself with out a little help from carb body warpage.also you can clean that idle air jet all day and its not going to stop surging.there enough said any comments ?

 

[Rivets]

Don't really know what you are asking, but will give you my opinion, based on my experiences. 1. Warping of plastic carbs is not as wide spread as you believe. It ales a lot of heat to distort a cab body. Yes, I have seen a few, but not enough for me to look for it first, but last. 2. I have found that dirty jets and bad springs will cause the majority of surging problems. I clean the jets with an ultrasonic cleaner and a fine wire and the vast majority of times it does the job. 3. Anytime you remove the carb, it is best to replace the gaskets before reinstalling the carb. This will over come minor body distortion.

 

[beg]

sorry my post was more of a rant but your advice is well taken.Before I rebuild this last carb I will go through it again.Most of the surging issue is with the air vane spring right?also if I drill out the main jet with a #68 micro bit and put in the b/s air jet will the engine run cooler due to more fuel consumption?

 

[impalass]

sorry my post was more of a rant but your advice is well taken.Before I rebuild this last carb I will go through it again.Most of the surging issue is with the air vane spring right?also if I drill out the main jet with a #68 micro bit and put in the b/s air jet will the engine run cooler due to more fuel consumption?

In my opinion the air vane spring will not cause surging if it is in good shape. Most of the time surging is cause by a lean mixture. The engine will run a bit cooler with more gas.

 

[Rivets]

B/S jet will not work. I would use a #70 or #71 bit to start with. You can always go bigger. The spring you are talking about is for setting governed top speed and will not cause surging. As posted surging is caused by a lean mixture 90% of the time. The other 10% is caused by a rich mixture and will normally be found on engines over 15hp.

 

[beg]

I broke down and popped for a complete carb that I assembled and installed but am going to use the old carb to play around with.the new carb surges but that probally is normal.thanks for the bit number

 

[bjl8691]

This is the easiest way to cure surging clean the carb completly change the needle and seat get a mikuni pilot jet or a briggs rtek pilot jet leave the main jet alone add some filter material under the primer bulb add a inline filter and 90 degree shut off valve no need for micro drilling jets I have 8 duraforce moeers and I have them all setup like this no surging they work great all the time

 

[Streamlight]

I found out that some of the duraforce carburetors got the wrong throttle plate installed at the factory, in fact the wrong throttle plates were from snow throwers that that have about a 1/16" hole in the center, while the correct throttle plate should be twice that size,about 1/8". I had a lawnboy 10550 that was surging, I checked the throttle plate and sure enough had the 1/16" hole in the center. Anyway after replacing the throttle plate, the surging stopped.

Part no. for the correct throttle plate is 98-7047,104-4431

 

[gregnauman]

So either of those part numbers are correct for the throttle plate? It seems from the lawn boy website the 104 number is for the 10550

 

[Streamlight]

So either of those part numbers are correct for the throttle plate? It seems from the lawn boy website the 104 number is for the 10550

I went with the 98-7047 part number , and it worked fine, I believe when I ordered the part, I looked up the part number from an early model lawnboy 10323 like a 1998 model or 1999. I recently checked to see what year they switched the part number from 98-7047 to 104-4431, so looking at the model 10323 again at partstree site it shows that they changed to the 104-4431 for model year 2001. I would say that your safe to order which ever part number shows up for your particular model and year of mower. You will also notice on the partstree site that the lawnboy model 10550 started in the year 2001 which shows the throttle plate to be # 104-4431.

I'll add a link here to good information on cleaning the Duraforce carbs and also info on the Toro Snowblower carb:

http://outdoorpowerinfo.com/repairs/briggs_lawn-boy_plastic_carb.asp