1990 Force 15 HP Outboard Running Rough! - Video Included.

comstox

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Guys I'm posting a video of me out today in 39 Degree Fahrenheit on the Connecticut River. (Hi my name is Glen and I'm a boat-a-holic.) Motor starts ok, one or two pulls. Idles fine, but any amount of throttle boggs it down: Then... all of a sudden... SNAP! Goes full throttle. I'm assuming there's a whole bunch of stuff that I SHOULD do, but what do you guys think is the main reason for this boggy lag???
BTW, I checked my speed when it was going fast and it was 22 - 25 mph and the boat stayed running smooth at WOT until I let off, then it went right back to the whole laggy, rough rider scenario.
Thanking you gurus in advance!
 

jerryjerry05

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Sounds like a dirty carb.
Ethanol delaminates the older hoses and gunk can end up in the carb.

Clean the carb.
Change the hoses.
Add a filter between the fuel pump and the carb.

​I'd also change the fuel pump diaphragm.
 

comstox

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Sounds like a dirty carb.
Clean the carb.
Change the hoses.
Add a filter between the fuel pump and the carb.
​I'd also change the fuel pump diaphragm.

I'll try those things first.
Thanks jerryjerry
 

fishrdan

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Check the fuel quick disconnect at the outboard, pump the bulb up and hold pressure on it while wigglin' the connector around. If gas leaks out, air will be sucked in.

Agree with rebuilding the fuel pump diaphragm, they were not rated for ethanol when the outboard was built. (I'd rebuild it for safety's sake.)

The outboard may have a BIM coil failing, common for these outboards. Check for a hot blue spark on both plug wires. It sounds to me like the engine maybe only running off 1 cylinder, then it starts running like a scalded cat when the bad coil kicks in. My Force(Gamefisher) outboard ran like the first part of your video when it had a bad BIM coil.
 

Nordin

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Agree with fishrdan, sounds it is running at only 1 cyl. and then the other kicks in and it perform as it should.

If you have a timimg light or an inline spark tester. Put it at top cylinder and check and then check at bottom cylinder.

To me it do not sounds like a fuel issue.
 

comstox

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My Force(Gamefisher) outboard ran like the first part of your video when it had a bad BIM coil.
I'll check into this. Are you thinking that at a startup idle the spark is enough to run smooth, but given too much gas it just won't ignite?
 

fishrdan

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Are you thinking that at a startup idle the spark is enough to run smooth...

Nope. These outboards will run incredibly smooth with 1 cylinder not firing and the only thing you'll notice is a bit lower idle speed, 50-100 rpm loss. Since this boat is new to you, you probably don't know if it's idling slow.

Nordin had good advice.

If it's bad BIM coil, Chicago Magneto supposedly makes replacements for $75 or so, or a $200 CDI ignition upgrade like I did.
 

comstox

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Nope. These outboards will run incredibly smooth with 1 cylinder not firing and the only thing you'll notice is a bit lower idle speed, 50-100 rpm loss.

The reason I asked is that I have an in-line spark tester, and if they BOTH spark a little I wouldn't be able to tell, but with what you stated (they can run smooth on one...) I should be able to try one plug and then the other to see what kind of spark I'm getting. Does that make sense?
Thanks again guys!
 

fishrdan

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Pull a plug wire and see if it runs, connect that plug wire back and pull the other plug wire to see if it runs. (Ground loose plug wires.) If it runs off each individual cylinder then at least you know the coils are firing.

Are you using a "light" ignition tester or one that makes the spark jump a gap? Could have a weak/failing coil that makes a light blink, but not good enough to jump a gap.
 

comstox

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Pull a plug wire and see if it runs, connect that plug wire back and pull the other plug wire to see if it runs. (Ground loose plug wires.) If it runs off each individual cylinder then at least you know the coils are firing.

Are you using a "light" ignition tester or one that makes the spark jump a gap? Could have a weak/failing coil that makes a light blink, but not good enough to jump a gap.
Good info! Thanks!
 

jerryjerry05

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Loose connections, low compression, bad spark plug, wrong plugs, dirt in the carb, bad fuel pump?

​Worked on my neighbors outboard: he said it had been running rough for the last 2 years??
​I removed the cover and the top plug wire was off laying in the lower cowl??
2 YEARS!!!! and he never took off the cover??
Not saying that you did anything wrong. Just showing that something simple could be the problem.

Sometimes it's a simple thing?

Do a comp test?
Change plugs?

Check the things I and the others suggested??
 

comstox

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Worked on my neighbors outboard: he said it had been running rough for the last 2 years??
​I removed the cover and the top plug wire was off laying in the lower cowl??

Vern - Copy.JPG
 

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comstox

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BTW I have not gotten a chance to get out there and take a look yet. We've had a hectic week here. But the weekend is approaching!
I just wanted to say 'thank you!' to all of you guys for your help and advice, with a little humor thrown in now and then!
THANK YOU!
 
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