1987 black max stumped HELP

[baycrabber1]

1987 black max 150 great compression, spark jumps the tester set at 40,000, carbs rebuilt. new ccms sport reeds, new plugs. has a miss and idles like chit until you hit around 1900 rpm. RUNS GREAT PAST THAT. pull the plug wires with it running and no 1thru 4 dosent change it much, pull no. 5 and 6 it almost kills the motor, checked ign system with a dva everything checkede out good. switched carbs around and it didnt change it HELP HELP PLZ

[transomstand]

Check for vacuum leak at the intake

[Dave Strong]

Bleed line condition and proper routing.

Dave

[baycrabber1]

sprayed around intake with carb cleaner and no change

[baycrabber1]

replaced all bleed lines when i did the reeds

[transomstand]

Is it spitting back through the intake when it misses?

[baycrabber1]

i had a hole in a bleed line and it spit back thru that. its really only running on no 5 and 6 i think

[baycrabber1]

got me stumped thats for sure i know a switch box does one bank so i dont think it would be that

[Alan Power]

Put it under load and bring the rpm up and try pulling plug leads again.
What do the plugs look like?

Did it only start when you swaped the reeds?

Check the float levels in the carbs.

Check your fuel pump, top 4 could be starved at low rpm.

[baycrabber1]

does the same under load its from idle to 2000rpm float level dead on

[baycrabber1]

fuel pump rebuilt

[transomstand]

Try pumping the bulb at 1500 rpm and see if it changes anything

[baycrabber1]

i will try that tomorrow what should i be looking for when i do it (n if it changes then what) wouldnt it run bad a full power? its only from idle to 2000

[transomstand]

i will try that tomorrow what should i be looking for when i do it (n if it changes then what) wouldnt it run bad a full power? its only from idle to 2000

Just trying to eliminate any type of fuel delivery problem by forcing fuel to it.

[baycrabber1]

will try a few things on sat ty

[ChrisCarsonMarine]

Check the function of the reeds by running the motor with the airbox off,see if there is air/fuel mix blowing back out of the problem cylinders carbs,could be out of place gaskets or improperly installed reeds?When did this trouble show up,and after what work was done,if any.Im working today if your still lost give me a call,305-394-3354,Chris

[transomstand]

Check the function of the reeds by running the motor with the airbox off,see if there is air/fuel mix blowing back out of the problem cylinders carbs,could be out of place gaskets or improperly installed reeds?When did this trouble show up,and after what work was done,if any.Im working today if your still lost give me a call,305-394-3354,Chris

He's going to rerun his ignition tests, he may have used an incorrect test procedure. I'm suspicious of that stator. If nothing turns up there, I'll advise him to call you.

Pete

[baycrabber1]

had the trouble before anything was done, no blow back from the carbs

[baycrabber1]

retested ign everything checking out good

[donmac]

I don't wanna sound like a smart A$$ ,but have you put new plugs in it!

[baycrabber1]

of course. i just back probed plud wires while running seems like its running on cyl 1 and 5 and no 6

[blowitup]

Firing order right?
How old are wires?

[200VEGAS]

timing light works good to check fire without pulling wires

[baycrabber1]

ty 200vegas but read previous post. dicnt pull wires just back probed them

[baycrabber1]

timing light can pick up a bad refrence signal, good old fashion grounding them out works best imo

[bigbluechevy454]

I'm gona say stator

[200VEGAS]

i'm learning,how do you do this?
i just back probed plud wires while running

[baycrabber1]

test lead alligator clip on other end to ground probe the plug wire

[baycrabber1]

too many years of getting zapped i hate it imo probing thye wire works well