Tune out accel pump on 2001 Virage 700 to fix acceleration bog?

[Bluedmax]

Hi All,

I have a 2001 Virage 700 with the single Keihin 40mm carb with accel pump.

After going through 2 engines from SBT (the first was defective) I can't get the ski to run right and have gone through everything I can think of (new fuel hoses, rebuilt carb and fuel pump, double checked jet size and location, set pop off and lever height, leak test block, etc.

I can't get rid of a bog off idle and am suspecting it's the accel pump. It will squirt when you give throttle, but takes a significant squeeze to start squirting (like half+ throttle). And when it does squirt it seems to start as more of a dribble or stream instead of a spray.

I've had the accel pump and nozzle all apart, cleaned both check balls, etc, but still can't fix the bog. I'm thinking now of ditching the accel pump and re-jetting the carb.

I've had the ski since new and it's now been a 2 year fight getting it to run properly again and I'm about ready to give up.
Anyone have any thoughts on doing this?

Thanks in advance

[Mr. GP1800]

Is it a lean bog or is it loaded up with fuel? Does it cough and sputter when you try to accelerate or does it fall on its face and almost die?

[Bluedmax]

It’s a lean bog, falls on its face, dies if u hit throttle too hard and don’t feather.

[Bluedmax]

Another question when performing the pop off test… should I be getting a clean “pop” every time I pump up the pressure? Sometimes I get a nice pop at the proper setting, but then many times it also starts oozing pressure out gradually and there’s no actual “pop”. Is this normal or does this indicate another problem? (I use wd40 to fill the area around the needle back up for each retest which always has a lot of bubbles).

[Bluedmax]

Another question when performing the pop off test- should I be getting a clean ÔÇ£popÔÇØ every time I pump up the pressure? Sometimes I get a nice pop at the proper setting, but then many times it also starts oozing pressure out gradually and there's no actual ÔÇ£popÔÇØ. Is this normal or does this indicate another problem? (I use wd40 to fill the area around the needle back up for each retest which always has a lot of bubbles).

[casey67]

"pop off" really is how much pressure it should hold/stay closed.
Soo in my opinion it actually "popping" seems as iff it sticks a bit.

There are carbs that do not have an accel pump, so yes it is possible to tune it to not boog on take off/eliminating the accel pump.
I have not seen it done on the single carb-most repairs dont go to that extreme, so there is no history/suggestion of what it will take as far as jetting.
That means you should do some reading on carb tuning, you will need to understand what you are doing and looking at to get it right. And be prepared to buy several jet sizes.

[Bluedmax]

Now you’ve got me thinking if that might actually be my problem… sticking needle and seat starving the carb for fuel?? When I pressure test and it “pops” it will do so at the specified pressure, then reseat at a lower pressure. When it “oozes” it will start allowing fuel to come through at a much lower pressure and the more pressure I apply the more it oozes. Can’t really say I can pinpoint a specific pressure in that situation.

[Bluedmax]

Well I ordered another carb rebuild kit, this time a genuine Polaris kit. Installed, double checked all settings, and still having the same issues... bog off idle and drops out of power band when cruising around 4500-5000 rpm. I'd like to try a different carburetor and there is a listing on Facebook Marketplace for someone selling a dual carb setup from a 700 SL/SLT for a reasonable price (much lower than the ebay listings). They're both Kiehin carbs and one has the accel pump. The biggest issue I can see is all the linkage (choke and throttle arms) are on the opposite side as mine. Anyone familiar with the specs on these carbs and if the one with accel pump will work on my 2001 Virage? Thinking I could possibly remove the butterflies from the choke and throttle shafts and swap the shafts around so they point to the other side???

[casey67]

Post a picture of your carb. Every domestic carb I have seen has cables at the front of carbs.

[Bluedmax]

You're right Casey, that's what happens when I've been staring at something for too long! The first 2 pics (carb 1 and 2) are the single carb from my 2001 Virage 700. The second 2 pics (carb 3 and 4) are from facebook marketplace of the dual carbs I was thinking about purchasing, supposedly off an SL or SLT. Doing more research now, it looks like this won't work as my singe is a 40mm and the dual setups are a smaller 38mm. I guess that's why all the used single carbs for sale are so much more expensive. I'm not sure if this is even my problem, was just hoping for a less expensive option to try. This is so frustrating.

[casey67]

That's 40mm feeding 2 cylinders, where the dual setup is 38mm for EACH cylinder. Up until 2000/2001 all 700 had dual 38mm carbs and ran well. They charge more for the single because it is from a later model. Starting with 98, 1050cc engines used 3 40mm carbs. (the 700 and 1050 are exact specs for each cylinder-at some point used same cylinders/pistons ) User named TXpro has a write up for twin 40mm on his Virage. My Virage has dual 40's but life has kept me from testing it.

The 96/97 SL/SLT700 carbs are jetted a bit strange compared to all other Keihin carbs, it shows up at higher rpm. But work well where you are having issues. It would be nice if the dual intake was included as well as the oil pump.
Make sure your reeds are sealed well-there is just that small strip of rubber.

Not to sound like a caveman/Tool Man Tim , but....
With a lean bog, more fuel IS the answer.

[32DegH2O]

Does your single 40mm carb have 4 jets in it?...just want to make sure your ski has the right 40mm carb in it...it should not be the same as a 40mm carb from a triple engine which has 3 jets. The single 40mm can easily feed two cylinders so that's not an issue.

[Bluedmax]

Yes my single carb has the 4 jets.
I read on another thread that someone was having issues and finally replaced the carb with a different one and fixed the problem. They cut the original carb open with a saw and found internal cracks in the housing. Seems like a rare situation, but I'm at the point where I'm thinking I need to try another carb. Just don't want to spend $300+ on ebay for another used unknown part.

[32DegH2O]

Yes my single carb has the 4 jets.
I read on another thread that someone was having issues and finally replaced the carb with a different one and fixed the problem. They cut the original carb open with a saw and found internal cracks in the housing. Seems like a rare situation, but I'm at the point where I'm thinking I need to try another carb. Just don't want to spend $300+ on ebay for another used unknown part.

Have you ever added seafoam in your fuel? If not, I'd give it a try as it will completely clean ALL of the fuel circuitry within the carb.

[Myself]

Did you check the intake gasket surface for flatness? I've found a couple of the Domestic 700's with warped surfaces.