Briggs Vanguard Issue

[C.M.C-175 0]

I currently have a Briggs & Stratton Vanguard 18 hp twin (Model #356447, Type 0087-E1) that is going to replace a Kohler KT17 in my C-175. I currently have the Briggs in a "Dummy" tractor, so I could get the alignment and the "bugs" worked out of it, before I actually install into my main tractor. I got the wiring issues and a few others worked out but there is one that I am still having. The motor will start very easily and run pretty smooth, takes throttle alright, clear up to full throttle. But it seems to have a "miss" in it about every 3-4 seconds. Also, after throttling down from full throttle, it will backfire through the muffler, throwing a flame about 6", and loud as hell! I have checked the plus, plug wires and adjusted the valves by the manual, I think correctly, and also adjusted the pick-up coils clearance, but still having problems. My next step is to get a carburetor rebuild kit and give that a shot, thinking that it may have some varnishing or a plugged passage. Other that that, I am out of ideas. Am I missing something? Also, I forgot to mention, the motor sat without being run for about a good 18 months. Thanks in advance for taking the time to read and am looking forward to some ideas!

Thanks,

Craig McDowell

[W9JAB 156]

I would go over the valves first,

I have used that motor on large

pressure washers and found that

after the first 100 hrs. a valve ajestment

is needed then after that it will be fine!

[W9JAB 156]

:omg: Rember that loose on the push rods

is better than tight. don,t let the noise bother you!

[mavfreak 11]

so this may be why my vanguard started doing this part way through the next summer after i rebuilt it :omg:

[Audioshot 2]

Is it running too rich and loading up? Check the plug color. That can happen, esp when powering back down and excessive unburned fuel from the main carb circuit ignites in the hot muffler.