253 won't start

[Natstar]

Thanks Ari666 i'll be leaving the carby alone for now. It's idling fine so no point changing it. I am hoping I found the problem but not having the right tools kinda sucks. I tested the spark plugs last night to see if its giving a weak spark and basically to get it to spark at all I had to hold it directly on the rocker cover so i'm now thinking it is a weak spark. They also looked quite good, no black soot on them but a healthy red colour so i have eliminated fuel is the issue. The dizzy cap looks pretty crap inside so I tried to sand it down with no luck. Would be easier if I had a volt meter to be sure but my thoughts are that when its under load and the rotor is spinning faster its not arcing correctly hence the choking when I accelerate. Either way it won't hurt to replace the cap anyway but would this cause the issues or just be part of the problem? It's electronic BTW.

 

[ari666]

yeah mate, change the cap and rotor button. even the smallest amounts of that white crap in there and i ditch them. sanding does help, but it increases the gap between rotor and button which decreases the spark at the plug.

i also suggest buying a cheap-o crap ebay dizzy cap and button. they are smaller and cheaper than the large cap bosch, and when i say cheaper i mean CHEAPER. think a cap and button will set you back 15-20 bucks, whereas the large bosch cap alone was 30 bucks last time i checked. but the big plus is that you have more room around your dizzy which means you have more scope for turning it.

just my opinion, im sure others will disagree.

 

[bjwynd]

actualy coils are lazy and thats why they have a gap without a gap the coil dosent produce that much amps to increace the amps they give them a gap wich makes the coil produce more amps and gives more spark how do i know this is my partners uncle is a mecanic

 

[ari666]

how do i know this is my partners uncle is a mecanic

so what you are saying is having a larger gap inside the rotor cap is actually better???


riiiiight...

 

[GreenGremlin]

bet it's the coil....
seen it a 1000 times before, dodgy coils always feel like a carb / fuel issue under acceleration.