Mercury 115 1988 I-6 WOT issues

[Faztbullet]

Disconnect the idle stablizer if not aleady discarcded, take a timing light asnd check each cylinder at rpm it acts up as you could have a switchbox failing when it switches into high speed winding of stator...

 

[sptjet90Reflexx]

I marked 1/2/3 TDC on the flywheel and put my timing light on 1/2/3 also. 1 looked ok but then started to look like it was 3. 2 and 3 were similar. Very clear I have a miss.

Also if I pull the spark plug wire from any of those 3 it runs exactly the same as with it plugged in.. ?

 

[sptjet90Reflexx]

update. I replaced the upper switch box and my WOT is doing great now. I still have a miss around Idle so either my 2nd switchbox is damaged or I still need to replace the trigger (which I will be doing when it arrives).

 

[Faztbullet]

a bad bias circuit will cause this actually the 2nd box is bad and damages 1st one, ohm the bias circuit as should be about 14000. Try installing the one you took off in 2nd ones place.

 

[sptjet90Reflexx]

Should I OHM from white/black to white/black between the switch boxes (with the white/black wire removed)? Is that what you are referring to?

Also if that is the wire you speak of it does look kinda... inflated? like the insulation got really hot at one point.. Should Probably replace that wire.

 

[sptjet90Reflexx]

Ah I c.. You mean from black/white of each switchbox to ground individually.

 

[sptjet90Reflexx]

.994k ohms going from the white/black wire to the box.. just under 15k ohms on each switch box white/black post to ground.

 

[sptjet90Reflexx]

Turns out I do have an idle stablizer.. I never saw it before but I guess that is what the white/black wire going to the Bias posts on the switch boxes is.. So this should be removed correct?

 

[sptjet90Reflexx]

I put the cowl back on the engine and it stalls and runs like crap.. I figure because the cowl is restricting air flow so I am probably running to rich?

 

[Chris1956]

The cowling will not restrict air flow to the motor. You might check for exhaust leaks from the midsection to powerhead joint.

 

[racerone]

The motor is 25 years old, why would the cover block air today ?----------------Look for issues with the spark plug wires and plug boots possibly shorting to the cowling.-----Dealer may help you find covers for the plug boots.

 

[sptjet90Reflexx]

Well considering the carbs were just rebuilt I assumed I could have the wrong mixtures and the motor is not going to breath the same with the cover off as it does on... of course there will be some restriction..?