[mikelf]

1987 2 cylinder with CD2 ignitionengine runs smooth at idle but under load it stalls and completely shuts down spark to both plugs are steady but you really have to look hard to see it jump the plug Is this normal?I've gone through the fuel system,new fuel pump,line fitting and hoses,carbs removed and cleaned every part of the fuel system looked new cleanohm reading for the sensor coil and charge coil are in spec my manual instructs to set a spark tester at 1/2" gap my tester does not perform that way but I can't see this spark jumping a 1/2" gap any idea??Thanks

[steviecops]

Because the plug gap is so small, you'd probably struggle to see it anyway. If you put a screwdriver (with an insulated handle!) in the plug cap, and hold it half an inch away from the block, the spark should jump the gap.Sounds like your idle speed may just be set too low. How does the engine run at other speeds?Good luckSteve

[fireman57]

Sounds like you have a powerpack that might have gone south. If you have a timing light you can hook it to each wire separately to test for spark. You can also put a nail in the plug wire and use insulated pliers to hold the wire half inch from the block. If the spark is yellow it is too weak to do any good. Must be bright blue.

[mikelf]

I made a adjustable spark tester and I can get a 3/8" steady spark from both,any wider and I lose it all together even at 3/8 it is a small flash not a popping sparktiming light flashes constant on both cylindersboth idle timing and advance are in specengine runs goods till it is loaded to plane the boat then it just shuts down,no spits or sputters just shuts off like you turned the key off I bypassed the kill switch and ignition switch with similar results thanks

[fireman57]

Change your powerpack.