1984 Bravo Carb Questions

I've played with the pilot screw adjustment out to probably 2 turns. It makes the sled run faster just off idle, but the actual idle remains unchanged, shuts off like a kill switch has been hit. If I put the slightest tension on the throttle cable, taking up the freeplay it will run like a champ, but right at clutch engagement rpm, ~3000rpm. The second I release that tension, it immediately and instantly dies, no chug, no stumble, instant kill.

The pilot jet was nice and clean, round hole when looking through it.

I've got a buddy with an ultrasonic cleaner, maybe I'm just not getting the passageways in the carb cleaned out enough with the compressed air and cleaner. I think I'm going to pull the carb off again after the weekend, take it apart and put everything through the ultrasonic machine and try once more. Like I mentioned above, I'm also going to rebuild the fuel pump on the off chance it doesn't move enough fuel at idle speed and I'm going to re-check my float adjustment again.

Everytime I take it apart and put it back together it gets better, So I think ultimately it is a dirty carb issue of somesort. Now everything is perfect except the idle.
 
are the rubber plugs in the right ports in the float bowl? had that one happen when someone cleaned a carb for me.
 
I don't think Bravos have plugs.

And 84 should he pre TORS. Some of what OP describes sounds TORSy, but the 84 should have a kill switch instead of TORS.
 
jjmoneysauce said:
I don't think Bravos have plugs.

And 84 should he pre TORS. Some of what OP describes sounds TORSy, but the 84 should have a kill switch instead of TORS.
Click to expand...

Yeah, all the diagrams I am seeing show an electrical switch that the throttle stop sits on. Mine appears to have been modified at some point, there is no electrical switch and the small throttle stop screw has been replaced with a long bolt and a nut to lock it. I know it is a pre-TORS sled but what would sit where the electrical switch would be in a TORS system?

I'll snap some pictures tonight.

I got out on it this weekend without having done any more work on it. Dragged a little Pelican 60 sled with the boys on it for 20km worth of laps of my yard and the little sled ran pretty good. I do notice it stumbles every once in a while, especially after a stint at higher throttle. It doesn't bog or stumble while you are on the gas, but when it comes down to low rpm after it will almost die when you go to pick the throttle back up for a second.

I still need to pop the carb back off and run it through the ultrasonic cleaner. I've also got a fuel pump rebuild kit on order and a fuel filter to put in it, I might be wrong but it is really acting like it is running out of fuel at idle for some reason. I know pumps normally go bad on the high side but I'm wondering if the filter is half plugged or the pulse side of the pump is getting weak and not delivering enough fuel at idle. The other thing that makes me think this is that if it does die off a stumble, or I let it die at idle, I need to pump 1-2 squirts of the primer to get it to fire again.

I also got out to cut some firewood with my little Stihl 039 my grandfather handed down to me. I just finished rebuilding the motor in it and giving it a general freshen up so I wanted a nice easy break it. This standing dead fit the ticket perfect! the little Bravo towed the load great. I do need to find a track for this thing before it spits it out the back, but that seems to be almost impossible for these little sleds.

I don't seem to be able to add pictures, but here she is in all her beauty! https://imgur.com/gallery/cpEI54r
 
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jjmoneysauce said:
A carb clean is definitely a good plan. I always start a new to me sled with a total fuel system rebuild.
Click to expand...

That's pretty much where I'm at now. I've cleaned the carb 3 or 4 times, each time with an improvement. My guess is I'm just not getting everything out of all the little circuits, combined with a 35+ year old fuel system and you have the recipe for weird behavior.

I didn't get a chance to get out to the sled last night but I'm hoping on Wednesday to rebuild the pump, put the new in tank filter in and run the carb through my buddies ultrasonic cleaner. If that doesn't do it, I might seriously consider looking for another carb just to try it but I think I'll get it. At this point I think I'm probably going to replace all the fuel lines too, just in case, there is nothing obviously wrong with them, but they are cheap, and very old.
 
Well, I haven't had a chance to do rebuild the pump or change the filter. But I did have 20 minutes today to take a look around again.
I found the problem.
It was TORS. I know this sled shouldn't have it, but it does. I found the switch in the belly pan with a broken wire where it connects to the harness. Jumped the two wires together and now it idles perfect.
I'm still going to rebuild the pump, replace the lines and put the new filter in for good measure but it sure was nice to figure it out!
 
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