90 hp Ignition Problem, Please help!

[BananaRiverBoater]

Hey guys,
I have a 1993 Bayliner Jazz jetboat with a 90hp force engine. It's a 3 cylinder two-stroke. My buddy borrowed it and stalled out on the water, frying the starter trying to get it restarted. When we got it home, I replaced the battery and starter, putting all wires back in their original place. There was one blown fuse I replaced. The engine turns over fine with no resistance, but I'm not getting any spark. There's no power at the coils, either. I'm unfamiliar with the switch box and trigger on these sytems. Can someone give me a set schematic and set of tests to figure this out? What readings should I be expecting when testing trigger voltage and/or resistance? Is there any way to test the switch box or the capacitor? Thanks in advance!

 

[john from md]

Re: 90 hp Ignition Problem, Please help!

First, check to see that your safety switch lanyard is properly in place. If it is not, you will not get spark.

Next, in order to work on these engines, even with our assistance, you will need a manual. The best aftermarket manual is the Clymer Force Outboard Shop Manual. You may also be able to buy an OEM manual but they will be pricey.

John

 

[pnwboat]

Re: 90 hp Ignition Problem, Please help!

Before you go through all that make sure you have disengaged the ignition kill circuit. Normally on most systems, there is a little plastic collar or clip you have to slip on to a button so that you can start the motor.

You can also disable it by unplugging the Black/Yellow wire that comes off of the switch box. See if you have spark after unplugging it.

 

[BananaRiverBoater]

Re: 90 hp Ignition Problem, Please help!

The safety plug was completely corroded, so I connected and shrink wrapped the wires together because the switch was useless. I unplugged the black/yellow bullet connector at the switch box and it made no difference. I'll have to drive up to the boat store sometime this week and get a manual. I wonder if I need a bayliner manual or the mercury manual? It's an hour drive so I was trying to get as much help as I could before taking that trip. Thanks for your input so far, please keep the suggestions coming!

ps-the boat ran without the safety plug when it was last used (over 2 years ago).

 

[john from md]

Re: 90 hp Ignition Problem, Please help!

The manual you want to get is the Clymer Force Outboard Shop Manual. That manual will have the wiring diagrams for your engine.

John

 

[pnwboat]

Re: 90 hp Ignition Problem, Please help!

When you say you shrink wrapped the safety wires together, are the wires actually shorted together? The metal conductor twisted together to make contact?

 

[BananaRiverBoater]

Re: 90 hp Ignition Problem, Please help!

Well there was an engine emergency cut off switch underneath the steering wheel that was completely corroded so I have those two wires where I can connect or disconnect them easily, for each test. But the actual safety plug that goes in by the ignition is corroded as well. I never had a plug in it before and the engine ran fine. But it did sit for two years. Do you think I should takes the two wires leading to that and connect them permanently?

 

[pnwboat]

Re: 90 hp Ignition Problem, Please help!

Normally on the Force type ignition systems (and others too), the safety switch is "closed" to kill the ignition. It shorts the signal to fire the coils to ground. When you connect the safety lanyard, it "opens" the circuit so the signal is not grounded and allows the signal to fire the coils. I would leave the wires off of the safety switch for now. Having an emergency cut off switch and a safety switch seems a bit strange to me. Sounds like maybe someone added/modified something there.

Regardless, pulling the Black/Yellow wire off of the switch box itself, eliminates any of those switches. You do have a switch box that all of the coils are connect to right?

Make sure all of the wires that come out from under the stator are free and not rubbed through on the insulation shorting them the engine block.

If you have a stator that has 2 yellow. 1 red, 1 blue and a ground, it has a low speed and a high speed winding. Blue to red should read 3250 - 3650 ohms. Red to engine ground 75 - 90 ohms. Yellow leads are for battery charging only. Make sure at least one of the leads you're measuring is disconnected from anything to eliminate any circuitry from affecting your readings.

Trigger leads should read 800 - 1400 ohms. White/black to Brown, and White to purple.

If all the reading are within specs, I would begin to suspect a bad switch box.

 

[BananaRiverBoater]

Re: 90 hp Ignition Problem, Please help!

Thank you so much for your help! I got the ignition working. The engine will not start still. I checked compression on all the cylinders and the bottom two were over 100, but the top one stops at about 80 psi everytime. Could this mean a blown head gasket? Shouldnt 80 psi still alow the engine to run? I'm going to remove and clean the carbs today. Should I consider removing the head and checking the gasket? Thanks again, I really want to get back on the water!

 

[john from md]

Re: 90 hp Ignition Problem, Please help!

Your engine is designed to have lower compression on the #1 cylinder than the others. However, your compression for number one should be 135 to 150, numbers two and three should be 145 to 160.

You need to pull the head off and look around, if you don't see any problems, put it back together with a new head gasket and don't forget to torque it to spec.

John

 

[pnwboat]

Re: 90 hp Ignition Problem, Please help!

Like John said, the compression seems a little low. Only two things that would affect that. Head gasket or rings. If the pistons have excessive carbon build up in the ring groves, it's possible that the rings have frozen up and are not free to move and seal against the cylinder walls. Bad head gasket is an easy fix. To free the rings up, you can use some SeaFoam, or Ring Free or similar product. All of the outboard manufacturers have additives specifically to free up the rings in the two strokes. SeaFoam seems to be the preferred product.

 

[BananaRiverBoater]

Re: 90 hp Ignition Problem, Please help!

I cleaned out the carbs and she started right up! It ran solid before my friend borrowed it, and I don't think he would overrev it or let it get hot. So it ran today for the first time in a longggg time! Thanks for your help guys. I may pull the head off just to inspect it before I take her back out on the water. I really appreciate the help guys and I'll make sure to ask you two from now on if I run into something. Thanks!