Super Jet Stripped fuel pump screw

[SubiacoCGB]

I'm new to jet skis and bought a '90 square nose SJ and am rebuilding the carb to take care of a problem with it chokin out at high to mid throttle. This is the first time I've rebuilt a carburetor and I don't have a ton of mechanical experience. Just the basics.

Just as I was finishing putting my Mikuni SBN 44 carb back together I tightened one of the screws too much and it gave way and spun. I knew I had stripped it. I'm pretty sure it's not the end of the world. I'm hoping it's not even that big of a deal, just a minor setback. The screw itself was different than the other three, so I don't think it was standard anyways.

I'm hoping I can just go to Home Depot or a machine shop and get a new screw that's got the same thread, but is just a little bigger in diameter. What do you think? Will I solve the problem or just cause more damage?

 

[Tyler Zane]

i would try a heli coil before i made it bigger. its kinda small tho and may not be available at your local parts stores like the more common size heli coils.

 

[zzylstra]

Problem is its a metric screw, in metric I think it's a m6 or 5 size screw but there are different pitches ranging from ultra fine to coarse threads per inch. I don't think going to the next size will fix the problem cuz it will be too big. If anything use the same size but a coarser pitched thread and attempt to tap it and use some type of jb weld. So when u need to take it back off u can drill it out to a smaller size, tap it, and it will be like new

 

[Tyler Zane]

Problem is its a metric screw, in metric I think it's a m6 or 5 size screw but there are different pitches ranging from ultra fine to coarse threads per inch. I don't think going to the next size will fix the problem cuz it will be too big. If anything use the same size but a coarser pitched thread and attempt to tap it and use some type of jb weld. So when u need to take it back off u can drill it out to a smaller size, tap it, and it will be like new

why is being metric a problem? i honestly dont know if the correct size heli coil is available but i would surly search before i used jb weld.

 

[zzylstra]

Because the size difference between the required one and the next on up is too large without drilling. Been around this shiitt for years. Not like a 6-32 to 8-32 size

 

[zzylstra]

Not saying its the right way either but his choices are limited

 

[Tyler Zane]

i understand what your saying, im just brain storming. cant sleep..



...it could work... lol

 

[vrizi]

I had this happen to me and just used a longer bolt, (same size) run it through and put a nut on the back to tighten it up.

 

[zzylstra]

That's a good idea too!! I had the fuel return nipple crumble out of one of my carbs, talk about screwed

 

[Tyler Zane]

I had this happen to me and just used a longer bolt, (same size) run it through and put a nut on the back to tighten it up.

this might be a winner right here.

 

[zzylstra]

^x2

 

[motoman96]

Why do people see the need to gorilla torque every damned part inside a carb? I mean come on, snug it up and call it good. Seems like the majority of carbs I tear apart I damn near need an impact driver to break them loose. It's a friggin carb people, not your head bolts.lol

 

[Tyler Zane]

even from the factory they can be tight as shlt. just did a carb job on a 1200 xlt and had to use my impact driver to get the thing apart. i dont even bother reaching for a screw driver any more until assembly.

 

[SubiacoCGB]

So I just ordered the helicoil kit the get the repair the threads. It was about $30 on Amazon. Napa auto parts, Grainger and several other places wanted like $50 for the kit.

VRIZI, that was a great idea and would totally work. I just saw your post though and had already decided to go the helicoil route. I'd rather get the threads repaired anyways rather than just riggin it. I'll let everyone know who it runs when I get it back together.

 

[Tyler Zane]

good luck bro, keep us posted.

 

[GSXR RACER MIKE]

I did the same thing as vrizi on one of my racebike carbs years ago, worked great, never leaked or came loose.

As far as not wanting to drill out the carb and use a larger screw, that's ultimately what your doing anyways when you drill out the hole for a heli-coil, your putting in a larger thread that the outside of the helicoil screws in to.

 

[SubiacoCGB]

Got it. Yeah, vrizi's idea is good. I am just doing the helicoil 'cause it'll be a little more "clean" in the end. Plus it'll be a good thing to become familiar with. I'll let y'all know how it comes out it the end. In the meantime, I hope everyone's out gettin some good ridin in and havin some fun.

 

[motoman96]

Problem is helicoils suck, timeserts are the way to go but......there's not really enough meat there for either option.