Stuck Carb Mounting Bolts

[SeaDooDoo90]

Trying to remove the carbs off a '95 XP and the four M8 socket cap screws will not budge. I've rounded out the two that are easier to access. Have tried a 1/4" hex bit, torx bit, triple square bit, shocking the screw head with some hammer pounds, applying a little heat, PB blaster from the underside. I've gotten both turned maybe a 1/2 turn and they will not budge any further.

I need to remove the entire assembly to have easier access. I see several sets of fasteners beneath the carbs attached to the intake manifold (I think Rotax calls it something different but it's an intake manifold to me). What's the simplest way to remove the entire assembly?

Once it's out, any tricks to remove the stuck socket cap screws? I don't think I've ever encountered bolts so badly seized

 

[mikidymac]

Salt water ski?

 

[SeaDooDoo90]

Salt water ski?

The previous owner used it in a lake, but it must have been an ocean boat at some point. Hard to believe freshwater would cause this kind of seizing

 

[SeaDooDoo90]

Finally got the last bolt out. What an absolute nightmare. For the 3 that weren't badly rounded, I was able to back them out with an impact from the manifold and then pound them out from the carb with a punch. The last one took hours with some skinny vice grips, heat and hammer shocks to the screw.

The throttle shaft assembly is now pretty buggered up from using the torch on it. The bushing is partially melted and I'm sure the sealing rings are gone. Is this component even serviceable, and if so, do they sell rebuild kits?

 

[mikidymac]

You are better off finding a clean used carb from someone like Westside Power Sports.

 

[SeaDooDoo90]

I was afraid of that. Thanks for the tip, I'll check them out. Also have a lead on one on Fleabay.

Well, since the rotax cover had to come off to remove the carb mount bolts, there has been some scope creep and I'm now replacing the oil lines as well. The small injection lines to the manifold were pretty old and brittle anyway. OSD sells some nice kits I'm going to buy. Getting to the oil return line off the block looks like a real bear without removing some exhaust components. I've read many times to avoid at all costs removing the head pipe / expansion chamber on the 951. Is the 717 similar or is removing the head pipe no big deal?

 

[mikidymac]

You don't need to replace the 8mm and 12mm hoses on these unless they are damaged.

 

[SeaDooDoo90]

Ok. They aren't damaged, but what if I'm changing oil types? The existing oil in the ski is goldish brown. I've never seen 2-stroke oil of this color (looks just like automotive oil). I've read that mineral oil is a safe option for these engines and I'm guessing it's what's in there. Compression is perfect so whatever it is was working.

I'm going to run Amsoil Dominator though and don't want to mix if it will cause an adverse reaction. I've read a clogged oil filter is the main concern with mixing.

 

[mikidymac]

I would run Amsoil Interceptor as it was designed and tested with the Seadoo and Skidoo Rotax engines in mind.

Siphoning out all the old oil from the 12mm lines will be fine.

 

[SeaDooDoo90]

Dominator is what I've got on hand, and since it meets the API-TC cert, what I'm planning to run.

Frankly, I would ordinarily never pay Amsoil's prices, but I got a deal on 6 gallons of the stuff from a shop that was closing nearby.

Sounds good. I'll remove the tank and dump out the old stuff, clean the lines with some gas and replace the inline filter. Any tricks on getting the old oil out of the return line? Or is there not enough in there to even worry about?

 

[SeaDooDoo90]

Regarding the fuel system, I will be replacing:

• Fuel lines
• Fuel selector valve (275500098)
• Fuel filter and o-ring (275500089 & 275500090)
• Fuel cap gasket (293250017)
• Tank check valve (275500087)
• Tank pressure relief valve (275500104)
• Carb rebuilds with OEM Mikuni

Anything I'm missing that could warrant replacing as an abundance of caution? I'd rather buy the parts now to have on hand, even if they don't need service yet.

 

[WhiskeyD]

The throttle shaft assembly is now pretty buggered up from using the torch on it. The bushing is partially melted and I'm sure the sealing rings are gone. Is this component even serviceable, and if so, do they sell rebuild kits?

Mikuni Throttle Shaft Rebuild 38mm

If carbs are in good condition and clean overall, just replace the throttle shaft and seals.

 

[SeaDooDoo90]

Mikuni Throttle Shaft Rebuild 38mm

If carbs are in good condition and clean overall, just replace the throttle shaft and seals.

Good to know - I didn't know this kit existed.

The outside body of the old carb is all galled up anyway though. Functionally, I'm sure it's fine, but it's now pretty rough externally from vise grips digging into it when I was at war with the seized socket cap screw. I ended up with a used carb in good shape for only $26+tax so no biggie. Small price to pay, along with my time, for buying a saltwater ski (and hopefully the only price).

In an effort to potentially help someone else down the road....If you ever encounter seized carb mount bolts like I did, DO NOT try to remove them with the carbs on the manifold. Remove the rotary valve cover off the block (four 13mm-head bolts). Careful not to let the rotary valve fall off the splines or you'll have to retime it (another mistake I made).

Once the rotary valve assembly is out, you now have access for an impact to the carb bolts. For the 3 socket cap screws I hadn't completely rounded out with my ratchet, my Milwaukee M18 nut buster made short work of them. Then you just need a punch to hammer them out of the carb bodies. It seems counterintuitive to apply so much torque to the bolts, but the hammering force from the impact prevents the fasteners from rounding out.