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Discussion Starter · #1 ·
Ladies and Gents, more help needed! Working with a 1998 Formula 500 Deluxe. 4950 miles on it. I've owned it for 3 years.

First time off the trailer was two days ago. Prior to un-trailering, I had started the engine on the trailer and the engine ran fine.

Primes and starts well with electric start. Idles for a 2-3 minutes, then dies. Then it becomes difficult to restart. After restarting with running throttle partially open, I can run the sled without issue in the snow. It runs crisp and clean for 2-3 minutes with great throttle response, then it BOGS! Badly. More throttle means it wants to die. Anything over half throttle and it wants to die even more quickly. I had to "feather" the throttle to limp it back home.

I left it in the yard over night.

Second day was exactly the same as the first. Started right up and idled for 3 minutes then died. Hard to restart. Needed partial open throttle to get it to start and needed to feather the throttle to keep it running. Made a short trip along the field line and it was crisp at first, then bogged up again and I needed to feather the throttle to get it home. Once I came to a complete stop, it died.

What should be my steps to diagnose and fix?
 

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I had a 99 500 deluxe. I had the same problems after paying to have carbs cleaned. Flooding out. Another Buddy and I argued about it. He was right. Needles and seat had a piece of old seat or something stuck.

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In this situation more info is needed. Next time it dies you need to pull the plugs and try to determine if the engine is getting to much gas or it's running out of gas. Start with seeing if the plug electrode/tip, is wet or dry.
 

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Discussion Starter · #5 ·
Needs to be primed again after it dies in order to get it restarted. Even with more prime, it requires mid-throttle to get it started again after it's warmed up (and dies).

I did check the spark plugs last night after I got it running and pulled it into the garage. Both appear dark tan and wet. So that looks good.

I checked compression and both are at 121.

I pulled the carbs and the started cleaning them. The mag side looks clean but the belt side looks dirty. I'll start cleaning them up and re-install tonight.
 

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Needs to be primed again after it dies in order to get it restarted. Even with more prime, it requires mid-throttle to get it started again after it's warmed up (and dies).

I did check the spark plugs last night after I got it running and pulled it into the garage. Both appear dark tan and wet. So that looks good.

I checked compression and both are at 121.

I pulled the carbs and the started cleaning them. The mag side looks clean but the belt side looks dirty. I'll start cleaning them up and re-install tonight.
Don't overlook the Pilot Jets, they are idle to 1/4 throttle. very often overlooked.
 

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Discussion Starter · #7 ·
Just a quick update. Pulled and cleaned both carbs. Mag side looked almost new, clean and ready to go.

PTO side, another story. Looked like a mile of gravel road was inside the float bowl. I had everything from dark colored gas/oil mix to gravel and black sand inside it. The needle looks like it was falling apart - it appears to have had a black rubberized tip on the needle to assist fuel cutoff in the seat. The Mag side carb also had a seat that looked like this one, but looked good and came to a point without any groove.

Well, without a replacement, the "rubber" point came off and I stuck the needle back in.

As in the original post, the engine still starts hard and requires pretty significant throttle to get it running. It does run better though, but still dies when I come to a complete stop. I'm getting more power through the throttle after I get it running. Still figuring it out.
 

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Needle and seats are a cheap fix. Seats wear out and become un-round. The neoprene tip is important for shut off.
 

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Have you checked the fuel line? Had an issue like that with an old Jag of mine and it was simply because something got stuck in the line that would let little fuel in and sometimes none at all which would cause it to be boggy or die.
 
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