300/440/550 js550 cant get it started

D

d3v0311

Location
Massillon, oh
aight i just picked up an 89 js550 the other day. the guy said it needed some carb work. he said it would bog down and just act really odd. when i got there he fired it up and it started. so i bought it. i took it home and rebuild the carb and cant get it to start. i dont know if he maybe just dumped gas into the carb itself before i got there or what. its getting spark. both cylinders are at dead on 120psi, but it just cranks and cranks and doesnt even try to start. i cant seem ti find a fuel on off switch so im assuming the "on" n "res" switch is the only fuel switch. I noticed also theres no fuel filter on this. dont know if it didnt come with one or he took it off for whatever reason. maybe a bad fuel pump? but not sure how to check that. its gettin air (obviously) its getting spark so the only thing left is fuel...any advice where to start? also it has kerker exhaust k&n intake n i asked him if he rejeted the carb n looked at me like he had never heard of such a thing. so im assuming it needs rejeted. BUT he had it started for a few seconds before i bought it so i dont understand it...thanks
 
D

d3v0311

Location
Massillon, oh
another thing, dont think it matters cuz it should still fire. but its got b8es plugs in it, the manual says it should have b7es plugs. would there be a reason that he had 8s in it instead of 7s..should i leave it or go get the right ones n put 7s in
 
S

Serio

Location
Minnetonka, Mn
I would try pouring a small amount of gas, or spraying some starting fluid into the mouth of the carb and see if you can get its started that way, then you know for sure its a carb issue. A few quick checks I usually do are: make sure the vacuum line is connected and not cracked, check and make sure the clear disks in the fuel pump (assuming it's a stock BN carb) are all in the right order/way as thiis easy to mess up. Also I don't know why people use 8's instead of 7's on their plugs, but I know I do because that's what mine came with and they work just fine. Hope this helps, and if you still can't get it started report back with what you tried.
 
Austin

Austin

Location
Loveland, Colorado
Do you have good gas in the tank? Did you put the fuel lines back on the carb properly(make sure in line is on the in , make sure return line is on return)? Also don't use starting fluid! Bad idea on two strokes. Use premix fuel if you pour some in the carb. I would go through the carb again and make sure it was rebuilt properly. Also bn carbs dont have jets just tuning needles. Did you leave the carb at the adjustments that it was at before you rebuilt it? But check fuel first then check lines then pull the carb again and go through it.
 
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