1988 Force 125 will not run. Strong blue spark, new plugs, fresh fuel etc.

[AnthonyJD]

Hello everyone,
I'm new to boats and I have had this boat out on the water a few times running great after installing 4 new coils (but it never liked to start good until the motor was hot). I went to fog the motor last fall and I couldn't get it started. I took the fuel line off before it enters the carb and fuel pulses out as the engine is turned over. I also cleaned both carburetors. I still couldn't get it to start. :mad-new: I covered the boat up and left it over winter.
This summer I got the urge to go fishing so I started working on the motor again. When I would check the spark it started out strong but quickly faded as the motor turned over. The stator failed a few tests and I replaced it with a new one. That didn't help. Then I replaced the CD modules with functioning used units. Now I have nice strong blue spark on all four cylinders. Still won't run. It fires a couple times every now and then. It also backfires sometimes when trying to start it. I measured the compression and here is what I found:

cylinder #1: 105 psi
cylinder #2: 125 psi
cylinder #3: 121 psi
cylinder #4: 119 psi
I realize this is out of spec (should be 145-160) but I would think it would still run.

When a friend manually advances the timing while I try to start the motor it actually runs for a couple seconds before quitting. I'm getting discouraged as I'm out of my element with boat motors, I just wanna fish! lol

Thanks,
Anthony

 

[procraftguy]

Re: 1988 Force 125 will not run. Strong blue spark, new plugs, fresh fuel etc.

Sounds like timming or the magnets under flywheel check top dead center on #1 and check out link and sink at top of page sounds like ur problem

 

[further]

Re: 1988 Force 125 will not run. Strong blue spark, new plugs, fresh fuel etc.

Cyl #1 compression too low. Not so much the actual number but the difference between cylinders is what's important. Shouldn't be more than 10psi Btwn them.

 

[foodfisher]

Re: 1988 Force 125 will not run. Strong blue spark, new plugs, fresh fuel etc.

You need compression, yours should run, spark, ok by you, and fuel, one backfire can ruin a fuel pump diaphram. My money is on a fuel starvation problem.

 

[procraftguy]

Re: 1988 Force 125 will not run. Strong blue spark, new plugs, fresh fuel etc.

If its fuel problem confirm by spraying mix gas in bottle in carbs if it fires that would be it but if u follow the sticky for carb and timming even with bad pump it will fire just wont stay running hope that helps with resolving problem

 

[Jiggz]

Re: 1988 Force 125 will not run. Strong blue spark, new plugs, fresh fuel etc.

First you need to make sure you follow proper starting procedures:
1. Prime the fuel primer bulb until it is firm
2. Placed control lever in fast idle (center push button and push forward or if different style pull out towards operator and push forward)
3. Engage choke by pressing down on key ignition; keep pressing down while turning key to on and start
4. Continue to crank engine until it fires or "sneezes" but not more than 10 secs; if it sneezed and not start. Reset key ignition to off
5. Try again but this time without engaging the choke; you can keep trying up to 3~4 times without re-choking to avoid flooding the carbs. And then try again with choke engaged.

I highly suggest you verify the idle mixture setting to be at 1 turn out from lightly seated on each carb. If the fuel was pulsating when you disconnected the fuel line it means the fuel pump seems to be working. To validate this install a clear fuel filter between the fuel pump discharge and the carb's inlet. Auto shops sell clear plastic fuel filter for less than $5 each. Just make sure you get those ones with a 1/4 or 5/16 inlets connectors or whatever your fuel hose size is. With a properly working pump this fuel filter should never go empty or even less than 50% full even at WOT.

 

[AnthonyJD]

Re: 1988 Force 125 will not run. Strong blue spark, new plugs, fresh fuel etc.

First I would like to thank all of you that replied and were willing to help a complete stranger! I took some of your advice and basically went through the fuel system and cleaned the carbs again really focusing on the needle and seats. I also double checked that the pump is pumping fuel. I checked that the idle mixture screws were correctly adjusted. It still wouldn't run so I double checked that I was still getting a good spark. It's doing what it was before, which is getting a nice strong spark and then stopping even though the engine is still turning over from the starter. So either I never fixed the original problem or its back. I tested the new aftermarket stator I installed and the resistance between leads was in spec. They were 330 ohms and they are supposed to be around 300 ohms (according to the instructions that came with it), so all good there. Then I checked the voltage output while the starter was turning the engine over, and bad news, it only generated around 50 volts AC!!! I have a blue point digital multimeter and there is a lag time so it doesn't show the immediate peak voltage but I suspect it is initially high and then quickly fades which coincides with the good blue spark that quickly stops. The other test I performed was a continuity check between the stator leads and the engine ground. It showed around 6 M ohms on all four leads. Does that mean it failed because that's a hell of a lot of resistance and may be for all intents and purposes infinity. What do you guys think? I was told by a boat guy that the flywheel magnets rarely go bad but I'm wondering if that's a possibility here... What are your thoughts guys and gals? I really appreciate your help!

Anthony

 

[foodfisher]

Re: 1988 Force 125 will not run. Strong blue spark, new plugs, fresh fuel etc.

Take the fuel pump apart and inspect the diaphram for hole or tear.

 

[Jiggz]

Re: 1988 Force 125 will not run. Strong blue spark, new plugs, fresh fuel etc.

Try the spray bottle diagnosis as mentioned earlier. This will readily tell you if it is electrical or fuel related problem. Then repost your results so we can focus on the problem.

 

[thelmuth]

Re: 1988 Force 125 will not run. Strong blue spark, new plugs, fresh fuel etc.

You really need a peak voltage tester/ DVA adapter to test the output. I thought I could do it without and have a high end Fluke multimeter as well as a Snap-On Vantage "scope". I was not able to get a reading close to proper voltage until I got a DVA adapter.

You can find them online for less than $30.

 

[jerryjerry05]

Re: 1988 Force 125 will not run. Strong blue spark, new plugs, fresh fuel etc.

Get another comp gauge.
Take another reading.
The results should all be within5-10#
10-20# can make it hard to start?
If I had 20# difference on my motors,I'd freak.
Make sure the plugs are out and the packs grounded.
Then the fuel system,some carbs have a rubber seal in the seat.
The Ethanol and the additives we burn makes the seal swell and shut off the fuel.
The wire connectors,replace them all.
The shrink wrap can hide broken wires.
Then check for TDC The flywheel key might have sheared.
The 88 flywheel, the magnet doesn't go bad. It comes unglued.
If it's turning with the rest of the flywheel it's still connected and probably good.

 

[AnthonyJD]

Re: 1988 Force 125 will not run. Strong blue spark, new plugs, fresh fuel etc.

I guess I'm not doing a good job of explaining myself lol. I apologize for this. I tried to post a video of the sparkplug so you can see how it sparks and then goes away but the file type isn't compatible.

Thelmuth: I'm going to order a DVA adapter but according to one source in a lot of situations you can times the number by 1.41 and that will give you a more accurate result. The way I understand it is the DMM takes samples and averages them and it turns out to be an average of the sine wave. By multiplying it by 1.41 you get the peak. But for the sake of being thorough I'm getting the DVA adapter.

I'm not saying there isn't a fuel issue but there definitely is an electrical issue. The spark starts and then just stops never to return until you stop turning the engine over and then turn the key back to the start position and turn the engine over again. The engine runs for a second at the most and the spark lasts for a second. Has anybody seen this phenomena before?

Thanks,
Anthony

 

[Jiggz]

Re: 1988 Force 125 will not run. Strong blue spark, new plugs, fresh fuel etc.

The electrical ckt for the ignition is totally independent from the battery ckt. In fact, this outboard can even be started without a battery using a pull cord just like a lawnmower pull start. So there is absolutely no electrical connection between the starting ckt and the ignition ckt except for the required starting rpm for the stator to generate enough electricity (around 150~180 VAC) to power the ignition ckt. You can definitely measure this using a DVM albeit you need someone to do the starting. Now the question, is there spark on the other plugs? Or are you just referring to a single plug losing spark? Have you checked voltage output on trigger wires? There are four sets of trigger wires which puts out around 5 volts output from each set, do you have this? If you have voltage outputs from the stator and trigger as mentioned above, and you are still not getting any spark on any of the plugs, the most likely culprit is either miswired CDM's or both CDM's are faulty. Is it possible all four coils could also be faulty? Yes, but very unlikely! While testing I recommend disconnecting the voltage charging rectifier just for an assurance it is not affecting the stator. Goodluck and repost your results.

 

[AnthonyJD]

Re: 1988 Force 125 will not run. Strong blue spark, new plugs, fresh fuel etc.

Jiggz, the spark issue is on all four plugs. Last year I installed four new coils so I agree with you I doubt they are the issue here. Just to recap I have replaced the stator with a new aftermarket unit. I was still having the spark go out so I replaced both cd modules with used ones. I thought the problem was corrected but either the cd modules never fixed the problem or the replacement cd modules have failed too. Like I said I already tested the new stator output at only 50 VAC on all four leads which is way too low. Meanwhile the resistance between leads is ok. I have yet to test the trigger leads but I will get right on that. So you don't think I need a DVA to test the stator output? I was hoping that's why it tested outa spec. I will try disconnecting the rectifier during my next test. I hate electrical problems!

 

[Jiggz]

Re: 1988 Force 125 will not run. Strong blue spark, new plugs, fresh fuel etc.

I do not believe you need a DVA to test the stator output. It is almost constant between 150~180 VAC depending on the rpm. Of course for the coils and CDM's you definitely need a DVA. You mentioned the original stator failed a few test, do you remember which test was that? Have you also inspected the integrity of the magnets on the flywheel? checked the integrity of the flywheel key?

 

[AnthonyJD]

Re: 1988 Force 125 will not run. Strong blue spark, new plugs, fresh fuel etc.

The original stator failed the resistance between the leads. I can't remember what the results were but I wrote them down and could find them for you if you want. It also put out 180 VAC and the manual called for 210 VAC. I started checking the trigger output as you suggested but the manual says I need a DVA to check the stator, cd module, and trigger output so I ordered one. The flywheel key is in good shape. How do I check the integrity of the flywheel magnets? The magnets being weak would explain a lot and the manual says it can happen but everyone says its unlikely. Once I get the DVA I will go through and check the cd modules, stator, and trigger and report back. Thanks Jiggz! By the way is your name a reference to fishing jigs?

 

[Jiggz]

Re: 1988 Force 125 will not run. Strong blue spark, new plugs, fresh fuel etc.

The trigger and CDM outputs may require a DVA adapter only because they are spike voltages rather than constant voltages like the stator output. Some DVMs are fast enough they can actually read such outputs without DVA adapters but most regular DVM cannot. However, the stator output is constant sinusoidal wave and constant with rpm and low enough it can be read by a regular DVM albeit read as rms or average (depending on the DVM). Since the rated output of the stator is 180 Vac + (peak) this translates to around 116~126 Vac (ave or rms) between each set of blue and yellow wires (there are two sets). DVA adapter is also required for reading coil outputs since it is too high (minimum of 15K volts ~22K volts) and the fact it is fast or spike and not constant. I'm not sure which manual you are referring to but my manual calls for 180 VAC output for the stator. In fact, this can be as low as 150 Vac when starting especially when doing the pull start.

Can you have another person hold the throttles open (halfway) using the control tower with a spray bottle of fuel mix in one hand while starting. If the engine fires continue to spray into the carbs and see if it will continue to run. I just want to take the fuel related problems out of the equation so we can focus more on diagnosing the electrical side. Obviously, if it continues to run on spray bottle the problem is more fuel related than electrical which I hope is the case since this is an easier problem to solve. Make sure you rig it for the muffs for cooling water.