Mystery Fuel/Carb Problem

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Dirt Squirt

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Thanks for all the great advice on this board! Now I've got an issue that I don't see addressed anywhere that I could use some help with:

I've got a 1996 Sportster. Last season I was having a bogging issue at max throttle. I discovered that If I pulled the choke cable out about 1/4 inch and held it there while running, it ran great. So I cobbled up a stop on the cable to hold it that far out and rode out the summer that way.

This winter I rebuilt the carbs - following the excellent articles and links on this site - Found them to be in good shape. The rubber bits were getting a little crusty so it was about time. I noticed the in-carb filters were perfectly clean.

Now I get it all back together, it fires right up. Idles perfect, comes off idle good, but it still bogs at high speed unless I pull the choke out that little bit- then it runs perfect.

Any ideas on what to look for? The main fuel filter is clean, and it appears as though all of the fuel lines have been upgraded to the newer style.

On the other hand, do I even need to screw with it? If it's not hurting anything to run it with the choke partially closed, I'm tempted to make it the next guy's problem. :D

Any advice is greatly apprectiated
 
I bought the OEM Mukuni rebuild kits. They came with two needle valve springs. I used the longer of the two as it appeared to be identical to the old springs. The Hi-speed screws are zero turns out.
 
Dirt Squirt said:
I bought the OEM Mukuni rebuild kits. They came with two needle valve springs. I used the longer of the two as it appeared to be identical to the old springs. The Hi-speed screws are zero turns out.
Click to expand...

The spring I was referring to is the "Pop off" spring. Did you use the one that was in the carb or replace it?
 
I guess I thought that was the pop off spring? It's the only spring in the carb except for the two on the HS & LS adjustment screws. It was clear that someone had rebuilt the carbs before me, so maybe they left something out? Judging from the rebuild instructions and pictures it seemed as though all the correct parts were there. There were two shorter springs included in the rebuild kit, but I assumed they were alternate springs to the ones I installed.
 
One more detail I left out. I noticed that the main (needle valve) jet was marked 1.25. all of the spec sheets I saw listed the available jet sizes as 1.5, 2.0, 2.5 etc. No where did it list 1.25 as being a stock jet size. I wonder if the guy before me might have put too small of jets in there?
 
I send every '96 Sportster out with the following when they come in for carb work:
1. 80 gram pop-off spring
2. 1.2 N/S
3. Pilot jetted @ 67.5
4. Main jetted @130

You have to spend some time with the arm adjustment on those, it needs to pop right at 55 psi to hold rpm's in a hard turn. Spend some time and pressurize the main fuel supply line, filter and both the main and reserve line right to the baffle to see if there are any air leaks.
 
Fixed it! I put a deposit down on a new scarab 195 and I'm picking it up next week.
That should take care of any carburetor problems. See you guys on the scarab forum.
 
Dirt Squirt said:
Fixed it! I put a deposit down on a new scarab 195 and I'm picking it up next week.
That should take care of any carburetor problems. See you guys on the scarab forum.
Click to expand...

Now that's what I call throwing money at a problem until it's fixed, LOL. That is awesome you bought one. I'm sure I speak for a bunch of guys here, POST SOME PICS!!!!!!!!!!! Congrats on the new toy.
 
Thanks all. I'm really looking forward to it. I bought Sparky (the sportster) last year. After a lifetime of outboards and stern drives, I wanted to try out a jet before I took the plunge. As it turns out, I love the way these things handle, so it was a no brainer for me to get a bigger, better one.

There are only three brands on the market as far as I could tell. Larson, Scarab, and Yamaha. The Scarab and Larson are both built by the same company in Cadillac Mi, but other than the Rotax, they are completely different boats. When I first got in the Larson, my thoughts were "wow, this thing is in great shape! What year is it?" Because it appears to be a brand -new 1975 boat as far as the styling and amenities are concerned. The Yamaha seemed more like a giant bath tub toy. It looked good, but to actually sit on the seats and 'flop' around on the boat, it didn't seem very comfortable or 'deluxe' to me. Especially for 27-28K! Seems like the Scarab addresses all that. There is a good youtube video out there that shows the difference. They cost a little more, but not that much, and I figure I'll appreciate the awesome features over the years more than saving a few bucks now.

Wish me luck!
 
Bummer. Gotta wait a week. Apparently buying a new boat is not like buying a new car. I figure you just drive in with your trade-in and float right on out of there on your brand new schooner. Nope. Got all the dickering done with the trade and paid for the new one, now they prep it and I pick it up a week from today. I guess it makes sense, the trade was sight-unseen (did the deal over the phone) and they have to register the new boat with the state, un-shrink wrap it,put the stickers on, trailer plates, and whatever else it is they need to do. I'll just have to put my tubing party on hold for a week.

They do take their new boat customers out for an orientation ride before final delivery, so I guess I still have an out - but I'm sure it will do just fine. I should have told them to hold onto sparky just in case.:facepalm:
 
Dirt Squirt said:
Fixed it! I put a deposit down on a new scarab 195 and I'm picking it up next week.
That should take care of any carburetor problems. See you guys on the scarab forum.
Click to expand...

Nice boat!!!
What lake do you ride in?
I'm just down the road a bit from you on Cedar Island Lk.
 
I'm on Maceday lake. Over the years I've had places on White Lk, Commerce Lk, and Pontiac Lk.
I love it here on Maceday, but I sure do miss the White Lake Inn :cheers:
 
As promised - here is a picture. At least I think it uploaded. Guess I'll know in a minute


scarab2.jpg


Yep! There it is. Great boat! It makes my old sportster look like a watering trough. WAY quieter that I thought it would be as well - that's an added bonus. I'm only running 3/4 speed or so (computer controlled) during the 10 hour break in period, but I'm loving it so far. The interior is super comfortable any way you use it, and even the base stereo kicks it. So far so good.
 
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