1970 60hp 3cyl bogging when throttling up

[Handyman72]

Gday all
Ok all electrics ohm checked
Carbys rebuilt
New coil
New plugs
New fuel tank,lines,pump
Points at 10 thou
WOT set 20 degrees with advance at stop,plugs out throttle at full
Throttlelinked
Timing sincd
Engine starts well and idles very slightly rough,engine revs well when in neutral, select forward or reverse (selectamatic) try to throttle up and engine starts to die,quickly disengage gear and engine will idle.select a gear again try to throttle up engine starts to die and stalls.
Engine then wont start for along time.
Primer bulb is not staying firm or hard.
Somebody please help as im really running out of ideas
Cheers

 

[Faztbullet]

Adjust the carbs in a barrel or lake to apply backpressure. Start at bottom carb and work way to top one. Make sure motor will run without carbs being cracked open with roller.

 

[Handyman72]

Adjust the carbs in a barrel or lake to apply backpressure. Start at bottom carb and work way to top one. Make sure motor will run without carbs being cracked open with roller.

Ok so the carbs have been adjusted in a barrel and also in the river,when it wont start for a while the carbs seem slightly wet at front of carb throat and when plugs pulled they are wet,there is plenty of spark.

 

[racerone]

What are the slow speed needles set at ?----A primer bulb on a hose does NOT need to stay hard after motor starts.---A very common mis-understanding on that simple item.

 

[Crosbyman]

old style carbs.... sounds like flooding....
float upside down ... ? inlet needle ok ?
tried doing a blow test on the carb ?

 

[F_R]

What new plugs did you put in? Hope not those surface gap things originally specified.

 

[racerone]

Low speed mixture needles must be set / adjusted for no bogging and smooth acceleration.----A minor mystery to some I believe.

 

[Handyman72]

Low speed mixture needles must be set / adjusted for no bogging and smooth acceleration.----A minor mystery to some I believe.

The only screw to adjust on the carbs are the idle mixture, they are all approximately one full turn out,when engine is running they can only be turned 1/4 each way and this causes rough idle not smooth,was running new surface gap plugs as original spec then put new normal plugs,both plugs ngk.
This hasn't made a difference,
Carby gaskets were original and new ones are rubber style.
Carbs were soaked in carby clean for 2 days.
No leaking from carbs
Floats are exact to spec,needles are rubber tipped,
This problem has only started since carburetor rebuild, the original problem was engine shutdown at high revs but found cracked coil and cracked brittle coil wires
Cheers

 

[racerone]

I guess I have to repeat.----Low speed mixture needles must be adjusted properly to avoid bogging !

 

[Handyman72]

I guess I have to repeat.----Low speed mixture needles must be adjusted properly to avoid bogging !

Ok so is it correct according to the manual with turning screw anti clockwise 5/8 turn from bottom or is there another procedure

 

[racerone]

I believe 5/8 turn out is the initial setting.----For a motor in good condition.----Then it needs to be fine tuned for actual conditions.

 

[Handyman72]

I believe 5/8 turn out is the initial setting.----For a motor in good condition.----Then it needs to be fine tuned for actual conditions.

Cheers mate i will do that today and see how it goes
Appreciate the help

 

[Crosbyman]

did you remove the top plug and clean the low speed idle chamber
in casethe small holes are not perfectly clean.

 

[Handyman72]

did you remove the top plug and clean the low speed idle chamber
in casethe small holes are not perfectly clean.

Hey mate
Everything is spotless so now checking a few other issues
Cheers

 

[Handyman72]

Cheers mate i will do that today and see how it goes
Appreciate the help

Gday again
Well stripped everything down again and at this stage when the engine was running i didn't notice it prior but it was arcing out under the flywheel.
After closer inspection the distributor cap has a hot spot where the coil wire is connected and runs right around the cap and the rotor is burnt as well.
Would replacing whole ignition with later system be better

 

[racerone]

I suppose the newer ignition is worth a try.----Just find a donor motor at $200 and open your tool box.

 

[Handyman72]

I suppose the newer ignition is worth a try.----Just find a donor motor at $200 and open your tool box.

Cheers mate will do