1990 force 150.... WHAT IS FIRING ORDER?

[waveblaster62]

My 150 will not start and backfires loudly. Like big firecracker... From what ive read here its either the flywheel key ( dont think so) or the firing order..... When i swiched from 12345 to 13245 it almost started. I may not have a spark a cyl.5 and will confirm that today when i get help. I dont know what a flywheel key is and have not been in there. But i have had the plug wires off many times the wires are all the same length except for #5 which is 4" longer and the only one that can reach it so i assume its ok.
I am at my wits end and have scoured the post, threads and web... Just no info on this exact motor firing order..... If it is 12345.... Can just one bad coil cause no start and backfires??? Please help.. Truly at wits end and desperate! Thanks in advance

 

[SkiDad]

Re: 1990 force 150.... WHAT IS FIRING ORDER?

I'm pretty sure they are in order 1 2 3 4 5. They fly wheel key is under the nut on the flywheel... it you take it off and put it back on make sure to torque it properly in foot pounds.

You could also check your compression on each cylinder by borrowing a compression tester from autozone, that is what I did. did you try cleaning the plugs or replacing them - they should be the flat style plugs. You can also get a spark tester for 10 bucks from autozone and test for that.

 

[tater76]

Re: 1990 force 150.... WHAT IS FIRING ORDER?

Top plug wire goes to top plug, second down wire goes to 2nd plug, so on and so on... Popping is usually a timing issue. It is possible your timing is out of adjustment. If you or anyone has had the flywheel off, and did not torque it back down to correct specs, the key will shear allowing the flywheel to shift slightly upon starting. This shift will throw off your timing. However, you can put a timing light on it without having to take anything apart, and see if its off.

But first things first like mitzy said, do a compression check, spark check, and make sure its getting fuel.

 

[waveblaster62]

Re: 1990 force 150.... WHAT IS FIRING ORDER?

top plug wire goes to top plug, second down wire goes to 2nd plug, so on and so on... Popping is usually a timing issue. It is possible your timing is out of adjustment. If you or anyone has had the flywheel off, and did not torque it back down to correct specs, the key will shear allowing the flywheel to shift slightly upon starting. This shift will throw off your timing. However, you can put a timing light on it without having to take anything apart, and see if its off.

But first things first like mitzy said, do a compression check, spark check, and make sure its getting fuel.

thanks to both for fast reply. Will do exactly as you say. Plugs are the flat style and been in unkwown amount of time since boat is fairly new to me. Will get on this asap and reply findings in next 24 to 48 hr.

 

[waveblaster62]

Re: 1990 force 150.... WHAT IS FIRING ORDER?

i'm pretty sure they are in order 1 2 3 4 5. They fly wheel key is under the nut on the flywheel... It you take it off and put it back on make sure to torque it properly in foot pounds.

You could also check your compression on each cylinder by borrowing a compression tester from autozone, that is what i did. Did you try cleaning the plugs or replacing them - they should be the flat style plugs. You can also get a spark tester for 10 bucks from autozone and test for that.

thx. I'll grab new plugs and follow your instructions from there

 

[waveblaster62]

Re: 1990 force 150.... WHAT IS FIRING ORDER?

Top plug wire goes to top plug, second down wire goes to 2nd plug, so on and so on... Popping is usually a timing issue. It is possible your timing is out of adjustment. If you or anyone has had the flywheel off, and did not torque it back down to correct specs, the key will shear allowing the flywheel to shift slightly upon starting. This shift will throw off your timing. However, you can put a timing light on it without having to take anything apart, and see if its off.

But first things first like mitzy said, do a compression check, spark check, and make sure its getting fuel.

i was double checking everthing in your reply and had 1 more question for now. if i make it that far, how do i konw for sure she's getting fuel ? thx

 

[waveblaster62]

Re: 1990 force 150.... WHAT IS FIRING ORDER?

i dont know if this helps but it was running when it was last parked 18 months ago. and i have never had flywheel off...??? okay thatsall i have until i get done what was suggested

 

[tater76]

Re: 1990 force 150.... WHAT IS FIRING ORDER?

There is a sticky/thread on this site somewhere if I remember correctly, that is called "Waking a sleeping outboard". This would be a great place for you to start. I will look for the link to it.

 

[Frank Acampora]

Re: 1990 force 150.... WHAT IS FIRING ORDER?

Coils are mounted 12345 and the plug wires go in order from the top down, But that does NOT mean that is the firing order. Look at the wiring diagram decal on top of the block to determine which trigger wire attaches to which terminal. THIS will set firing order.

Unfortunately, I have just started with my 150 and have not had problems so I do not yet know the correct firing order offhand.

 

[johnbottsr]

Re: 1990 force 150.... WHAT IS FIRING ORDER?

Not sure if this will help you, but according to my manual (for a 1991 J - 1994 150HP) the trigger leads are:
#1 - Brown
#2 - White
#3 - Violet
#4 - Black
#5 - Yellow
Ground - white / black

 

[jerryjerry05]

Re: 1990 force 150.... WHAT IS FIRING ORDER?

1 5 2 3 4 Firing order.
There should be a decal with the wiring diagram on the motor??
Compression test? This should have been the FIRST thing you did.
Like the others said the plugs go in order 12345. They get their firing order at the trigger/packs.
Check the flywheel for sheared key.
Remove the top plug and insert a thin screwey and rotate motor(by hand) to pus the driver out as far as it goes.
Then check timing marks on the front of the motor. It should be real close to TDC.
The flywheel key can shear just by turning the key, just by turning the key off. A little cough,stutter,backfire can shear the key?
When my boat was new. Boat ran great. Went fishing, and on the way back in, the stbd. motor wouldn't start. I checked everything,took it to work and the boss said check the flywheel key. That was the problem.