90 mercury firing order. 3 cylinder 2 stroke

[Gatorkiller67]

Got a new power head. Apparently it's a 132 firing order. My electrical is a 123. Tried swapping coil wires. Still misfiring. I'm thinking its the flywheel. Mines a 9007. Anyone know which flywheel the 132 block takes?

 

[Maxz695]

Re: 90 mercury firing order. 3 cylinder 2 stroke

I seem to be having the same issue i,m running a 70 HP 1979 123 order with a 1982 crank 132 order. Pops when I gas it. Does yours misfire at low idle speed?

 

[Gatorkiller67]

Re: 90 mercury firing order. 3 cylinder 2 stroke

Yes it does

 

[Maxz695]

Re: 90 mercury firing order. 3 cylinder 2 stroke

Mine idled fine with the older switchbox stator and flywheel with the newer crank. I pulled it back down due to the backfire. I,m adding a piston as one had corrosion. and I wanted to swap the reeds as well as I had a leaking seal on the lower endcap. If yours is backfiring at idle I would try using greyish or green can,t tell what it is (flywheel) first depending on the stator. and trigger. I,m hoping I don,t have to change over to the 82 set up. $$$$ money is really getting deep. Having the plug surfaces welded tomarrow morning.

 

[ajgraz]

Re: 90 mercury firing order. 3 cylinder 2 stroke

Got a new power head. Apparently it's a 132 firing order. My electrical is a 123. Tried swapping coil wires. Still misfiring. I'm thinking its the flywheel. Mines a 9007. Anyone know which flywheel the 132 block takes?

Max and I are in very similar situations. He is rebuilding his 79 70hp with a newer crank, I just replaced my 78 70hp with a 1988 60hp powerhead; both of us went from 1-2-3 to 1-3-2 firing order. I believe both of us are using our original 78-79 ignition and fuel systems (I am anyway).

I first tested mine switching the plug wires between 2 and 3 coils, and ultimately switched those back and made a longer green/red switchbox-to-coil wire and just swapped the order of those wires between the 2 and 3 coils. (Same difference, just wanted the plug wires to match what's embossed on the coil cover.) I had some popping and lean sneezing at first, but once I got my timing and carb idle screws dialed in on the new powerhead, all that went away and now it's idling smooth as silk.
(Real on-the-water test this weekend)

What year was the original powerhead, and what year is the new one? Did you swap ALL the ignition stuff (flywheel, stator, trigger, switchbox) and fuel stuff (pump, carbs) from the old to the new? As long as the upper end cap (where the trigger resides) and the throttle/timing arms are the same between whatever years you're using, the timing and idle should be able to be set no problem, regardless of the new firing order.

Why did you need a new powerhead anyway? (What happened to the old one?)

 

[Gatorkiller67]

Re: 90 mercury firing order. 3 cylinder 2 stroke

I think it's a 96 model I have

 

[ajgraz]

Re: 90 mercury firing order. 3 cylinder 2 stroke

I think it's a 96 model I have

So both old and new are 1996? I'm not so familiar with Mercs newer than late 80's; how did firing order change?

 

[Maxz695]

Re: 90 mercury firing order. 3 cylinder 2 stroke

He got a newer power head i believe he was trying to post 2007 and had an earlier model like ours 78 79 ish He may have to do as instructed by you and adjust the timing for the newer model powerhead. Between the three of us I believe we are gonna find out if the older electrical systems are compatible with the newer firing order and the crank Journals. It all comes down to ajgraz and his test run a WOT and a hopefully favorabler reply indicating no isseus or bad news. Your the man Ajgraz. Make us proud

 

[Gatorkiller67]

Re: 90 mercury firing order. 3 cylinder 2 stroke

I don't know what year my old power head was. Early 90s I think. I fish commercial so it's been replaced before. I burnt a piston and got a deal on this new powerhead. Serial number on my flywheel is 9007.

 

[Maxz695]

Re: 90 mercury firing order. 3 cylinder 2 stroke

Truthfully I don,t know about the flywheel issue.Possibly someone eles on here may. Seems to me if it did need a different one it would also need a different stator and possibly flywheel hub and trigger. Reconfirm that you firing order is set correctly. Coil one (Bottom coil) as marked plug wire goes to lowest cylinder being cylinder 1. Then the #two coil (Center coil) plug lead is going to the top cylinder to fire second on number 3 cylinder, and last that your #3 coil (TOP coil) plug wire is going to the center spark pug to fire last. This would be with the original wiring from the switch box as original marked for the color coded wires to the coils. Meaning just swaping the pug wires to acomidate the 132 firing order.the only time I ever had an idle backfire constantly was on my 40 HP I ran for a long time then the engine died got towed in and the next day while searching found for some reason the plug wires where revesed. I had changeds a fouled plug a good distand back and may have reversed the wires then. I swaped em and she ran fine scince then.

 

[ajgraz]

Re: 90 mercury firing order. 3 cylinder 2 stroke

Gator, you really have to start answering some of our questions if you want help. Did the ignition parts from the old powerhead get transferred to the new? Or did the new come with that stuff?

I don't know what year my old power head was. Early 90s I think. I fish commercial so it's been replaced before. I burnt a piston and got a deal on this new powerhead. Serial number on my flywheel is 9007.

Hmm, could be a mish-mash of parts years on there then. Some quick web research indicates that there were a number of changes in part number for the stuff that is on topic here (block, crank, flywheel, trigger, stator) in the Merc 90hp 3 cyl's right around 1993-94 (probably to to accomodate a change to 1-3-2 firing order), then another change in most of the ignition part numbers in mid-1996 (for what purpose, I dunno, maybe to swap trigger firing order to avoid crossing wires over at the coils? Maybe they included one of those idle stabilizer doo-dads?). They all supercede to different current part numbers, so you basically got three groups of ignition parts:
1) 90-93
2) 94-mid 96
3) late 96 to about 98

And two groups of block/crank parts:
1) 90-93
2) 94-98

If your original powerhead is 90-93, and your new powerhead is a 1996 (or actually 1994 and up), I am thinking you might need to acquire newer ignition parts. It is very possible that the mounting area on the top of the block where the trigger rests changed between 93 and 94 (and/or the location of trigger magnet in the flywheel, trigger points in the trigger, their relationship to the timing decal and the timing pointer, all sorts of possibilities), and thus a pre-1994 trigger and flywheel (which I am assuming you are using) may not allow you to set timing accurately on the newer powerhead.

So how about for a start we try to figure out for sure what years the original motor was and the new powerhead is. Perhaps the original motor has a serial number plate riveted to the clamp (up on top of the tilt tube area), and perhaps the new powerhead has a serial number stamped into it somewhere.

 

[Gatorkiller67]

Re: 90 mercury firing order. 3 cylinder 2 stroke

I have 3-4 3 cylinder motors for parts. They all mixed up

 

[Maxz695]

Re: 90 mercury firing order. 3 cylinder 2 stroke

View attachment 171845View attachment 171846View attachment 171847View attachment 171848 These are pictures of my 123 1979 70 HP switchbox See if the markings are the same as the switchbox your using to confirm the firigs order on the box is 123. You cannot use a different stator trigger or flywheel and expect them to be compatible. Althgough some may be. You may have coil issues timing issues voltage issues on the like mine frankinmotor. Your using a 132 crankshaft with a 123 switchbox should be no problem there swap 3 and 2 cylinders. The rectifier is the same. The stator the trigger and flywheel must be for the switchbox you have installed. The timing should be set according to the 132 firing order. Just came to me while pondering. See what plugs the 132 crank uses. It may be different then the 123 crank set up. becuase your usign from what I understand to be 3 to 4 different engine componants you may be using a 9 amp stator wirh a different trigger instead of a 16 amp stator on a switchbox not conformed to work with these voltages and positioning of the upper end cap

 

[Gatorkiller67]

Re: 90 mercury firing order. 3 cylinder 2 stroke

I was told this is a 132 firing order engine but rolled the engine over by hand #1 cylinder tdc then # 2 cylinder is right behind it -turning engine clockwise. Then #3. Seems like a 123 firing order engine. Am I right?

 

[Maxz695]

Re: 90 mercury firing order. 3 cylinder 2 stroke

Then thats what it is I asked you earlier to check which cylinder came to the top after #1 never got an answer from you. I think it was on a different post. if # 2 cylinder TDC follows #1 cylinder before #3 then the firing order is 123 Set the firing order on the switch box and coils to the original markings on the older switchbox pictured above is a 123 switchbox 70 HP. If I,m mistaken about the info on the cylinders I appologized and it was another person having the same issue

 

[Gatorkiller67]

Re: 90 mercury firing order. 3 cylinder 2 stroke

Motor was at a friend of mine. Sorry for the delay.

 

[Gatorkiller67]

Re: 90 mercury firing order. 3 cylinder 2 stroke

After looking at my stock at home, I have 2-132 cranks and 1-123 crank. So I could have used the trigger and flywheel off a 132 powerhead. I'm not sure which one to use on my new 123 powerhead. And ideas on part numbers?

 

[Maxz695]

Re: 90 mercury firing order. 3 cylinder 2 stroke

The trigger is the same for both. I,m inquiring a 1983 block for my 1982 crank I at present am still working on the 1979 Block with the 1982 crank with the old 123 electrical set up. It is confirmed the 123 electrical works fine on the 132 crank. I recieved that today from Ajgaz. He took his out with no problems as far as the older electronics and the newer 132 crank, and I also asked him If the 1983 trigger would work with my 1979 electrical and it is confirmed compatible. Without serial numbers, model numbers and a year for the flywheel it would be impossible for me to tell you as first of all you have a 90 HP. Second I cant see them. thirdly you should know or have marked which is which and what goes with what

 

[Gatorkiller67]

Re: 90 mercury firing order. 3 cylinder 2 stroke

Mechanic called says its running. Was the wrong electronics for this block but says he swapped some wires around and got it running. I'll find out what he did and post it Thanks to all!

 

[Maxz695]

Re: 90 mercury firing order. 3 cylinder 2 stroke

Good luck happy and safe boating