Need Help.. I think it's the switchbox

Hello everyone! I recently picked up a old 1989 Aquasport with a 90hp 2 stroke Mercury (boat has been sitting for 10 years). I did some trouble shooting and replaced the burned "trigger assembly" and I was in the water the following week with no issues!

The problem I'm having now is I'm getting random starts/spark and I think everything is pointing to the switchbox...... I checked spark and only had fire on 1 cylinder...I switched coils and had spark on all other coils.. so not coils.

I grabbed my trusted Snap-On hammer and lightly pounded on the switchbox and abracadabra it started right up!!

I don't feel comfortable taking it back out on the water until I fix the electrical Gremlin... Any help would be greatly appreciated!

If it ends up being the switchbox, is there a better brand out there? I have seen Teleflex,CDI,Mallory,etc.

Thanks

Re: Need Help.. I think it's the switchbox

I've never used a hammer on a switchbox but seriously do not recommend it.

Cranking speed is a major factor, minimum 300 RPM or the stator will not generate reliable spark, so check the battery, all connections, and starter comm and brushes.

Re: Need Help.. I think it's the switchbox

have you ohm'd out the stator, and checked the voltage, I dont see how tapping the cdi couldfix it, and its not a good idea....

Re: Need Help.. I think it's the switchbox

I grabbed my trusted Snap-On hammer and lightly pounded on the switchbox and abracadabra it started right up!!

Click to expand...

Havnt used a hammer but have took thumb and pressed in the potting compound and did the same thing as internal rectifier in switch box looses ground...

Re: Need Help.. I think it's the switchbox

Thanks for the great tips guys! Here's and update... Impedence on both the stator and trigger are correct. I did notice that the ground was kinda loose (motor side) and ran another ground from battery to motor and also added grounds to areas around the motor. I while inspecting a few thing on the motor, I notied that one of the spark plug leads wasnt really making a good connection.. After installing a fresh battery...... IT STARTED RIGHT UP!

The problem is that I did so many things to the motor at one time, I realy don't know what the true issue was.

I ended up ordering a new switch box, because the old one was at least 15 years old.

Do the individual coils go bad often?

Thanks

Re: Need Help.. I think it's the switchbox

Do the individual coils go bad often?

Click to expand...

Vary rarely...

Re: Need Help.. I think it's the switchbox

Thanks again everyone for the info! Most of the day was spent working on the boat and it startered up evey time! Another question I have to throw out there.... I already ordered a new swichbox since the old one was 15+ years old and it's coming in Wed. Do the swtchbox work randomly? I was told that they either work or they don't.

Thanks again for your help.

Nebrido

Re: Need Help.. I think it's the switchbox

Contrary to whats posted they can work randomly....

Re: Need Help.. I think it's the switchbox

Guys, I got the new swithbox in and it seems to run better and stronger. The weird thing is that the motor idles higher... Just a few question.

Where should the idle be set at? Use timing or RPM? Thanks!

Re: Need Help.. I think it's the switchbox

Warm the motor up in the water or test tank, then do a link and syc to the motor. Idle speed should be 650 to 700 RPM with the motor in forward gear and warm. The idle cannot be set correctly with the motor runnig on muffs as there is no back pressure on the exhaust nor drag againest the prop. You can runn the boat aginest a dock or a cutbank on a river to set everything . Just have all the tools needed tied to the boat incase you drop them in the water.
Oldman570