coil problem?

[pookie1135]

have 04 90 hp merc idol bad.check comp 120 psi on allcycl.pulled spark plug on number 1 ran like crap . pulled #2 ran like always. pulled #3 ran like crap.checked spark is good on all cycl.is coil bad or am i missing something.any help i would app. tks

 

[Charlie61]

Re: coil problem?

you need fuel , air and spark to make it run could be cards need rebuild. or fuel pump rebuild think I would do carduretor first.you can buy kit online at low cost

 

[pookie1135]

Re: coil problem?

you need fuel , air and spark to make it run could be cards need rebuild. or fuel pump rebuild think I would do carduretor first.you can buy kit online at low cost

i did rebuild carbs and pump.nothing changed

 

[oldman570]

Re: coil problem?

You should never run the motor with the plugs disconnected as damage to the switchbox is common when there is no ground for the electricty to flow to. Is there any sign of fuel on the missing plug? Have you changed plugs around to see if that plug is bad?
Oldman570

 

[pookie1135]

Re: coil problem?

i grounded the plug wire.brand new plugs.yes plug is wet tks.

 

[Charlie61]

Re: coil problem?

it sound like it's time for service manual. if you have spark ,air, and fuel I would think timing it off. them you rebuild cards and pump you could alway check timming

 

[pookie1135]

Re: coil problem?

checked timing is ok.was thinking coil might go bad under load.

 

[Charlie61]

Re: coil problem?

sorry I do not know more , there it a trigger that dose something with the timming but I don't know how it work. hopfully someone read this and help you out

 

[oldman570]

Re: coil problem?

It could be a coil going out or a switchbox going bad when the motor gets warmed up. A noon spark tester used to check for spark at the plugs should show which plug is having a problem. Then it just a simple change of the coil, with one that is known to have good spark, and see if the miss goes with that coil or stays where it was. If it moves the coil is bad if it moves the switchbox , stator, or trigger is going bad. Inspectionand testing of the wires to the stator and trigger will tell if they are good. My bet is that the switchbox is the trouble. JMO,
Oldman570