engine trouble....rebuild carb??

[Woody]

whats up everyone...

towards the end of last year...i started having some issues with my "other" ski...a 90 650sx. when i would go to plane off, i would have to lean forward on the tray to get the thing off on plane. it was slow to accelerate, and lost some top end (maybe 4-5 mph). no starting problems...no cavitation problems (other than the typical "650 slide" in turns lol).

i checked the compression....160 front 165 back (on completely stock 650)...so i figured that was pretty good. I popped off the carb and found the choke had totally been rusted...however the rest of the carb looked good.

i started taking it apart and took some pictures. keep in mind i'm new to the mechanics of a carb...so if i had to rebuild it I probably could...however I don't know what a carb that needs to be rebuilt looks like.

anyhow...here are my questions:
1. do you think it is could be the carb causing me these problems?
2. should i just buy a new carb for this thing with all the rust on the choke? there doesnt seem to be any other damage to the carb besides the rust
3. should i take off the pump to make sure nothing is cracked? the prop didnt look too bad while looking through the ski...there may be some damage to the pump shoe or something else in there.
4. is $50 a fair price for a carb rebuid kit and external fuel pump rebuild kit?

thanks!
woody

 

[Rockstar]

You should rip the choke out of there anyway and get a primer kit for that bad boy. I dont think thats what is effecting it though. you usually dont have to actually purchase a rebuild kit. You can usualy get away with just taking everything apart and cleaning it with some carb cleaner.

Are any of the diaphrams ripped or torn?

 

[Woody]

i dont use it enough to put a primer in. i dont take it in the ocean and it fires within the first 5 revolutions every time.

i haven't gone in all the way into the carb yet...i just took off the first cover to get to that black diaphram. there was some kind of wrinkling on the bottom of the black one...does that affect anything?

 

[faster7581]

have you replaced your spark plugs, and remove your plug cap (twist off) cut the plug wire back 1/2 inch, spray sum lube on the wire and thread the cap back on.. your carbs looks good from the pics, remove the jet plate and check under there.

 

[Waternut]

The diaphram still looks pretty good. I would imagine the carb is fine based on the fact that you didn't indicate any kind of hesitations/bogs during acceleration.

As stated earlier, it could be the plugs and those are super cheap so it can't hurt. Your spark plug wires could be corroded real bad too. Lay the plugs on the head attached the wires and crank it to see how strong the spark is. If it's weak, trim the wires back until the wire is good and get new fittings (not sure what the piece inside the boot is called).

The other thing you could check is the pipe. Make sure the bolts are secure. If they feel a little loose, you might want to pull them off and replace that gasket. An air leak in the pipe can cause a huge power loss that's quite hard to figure out!

The pump and prop are pretty easy to figure out. It doesn't sound like you have an air leak in the pump. Just look undernieth the ski, remove the intake grate, and check the prop and pump shoe. Shouldn't take more than 5-10 minutes. I wouldn't remove the pump unless you have to because the 650's have to be glued back into the hull.

 

[Woody]

yeah the plugs have gotten changed every year...and i just cleaned up the wires...

i'll have to check out the spark and see how it looks. wouldn't i have trouble starting if i had a weak spark? i popped off the intake grate and the pump shoe looked ok...and prop looked ok as well. interesting to know that the pump has to be glued back...that would've stunk. i guess i'm just going to have to wait until i put it back in the water and see if the spark wires have helped any.

thanks for your guys input. i'll check the pipe and get back to you.

 

[itismejoshy]

woody, on the other side of the carb(no shown) there is alittle black looking thing that is a filter and sometimes gets clogged, check it while your in there! hope you figure it out.