98 force 120hp

ol salty

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May 26, 2016
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4
I have a 93 Bayliner Trophy 2302wa with twin 120s. I have had problems in the past with reeds which would cause rough idle, but one engines idles fine but when you give it gas it revs up but then starts to misfire and will die if I don't let off the throttle. Possible stator problems?
 

Jiggz

Captain
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Oct 23, 2009
Messages
3,817
Stator is a possibility but always start with the easy ones. First, validate the flywheel key is not sheared by zero'ing the #1 cylinder with the flywheel TDC marker. Next double check the spark plugs are not fouled. Then check the fuel delivery system to make sure the fuel pump is delivering the proper amount. A clear fuel filter installed between the fuel pump outlet and the carbs' inlet will be very helpful on this one. While rev'ing and when it starts to misfire, does pumping the primer bulb smoothens it out? Does the primer bulb collapses when it starts misfire? Next check make sure the carbs jets are not clogged and the float is properly set. Then you can do resistance check on the stator. 800-1000 between the bl to bl/wh and red to red/wh.
 

jerryjerry05

Supreme Mariner
Joined
May 7, 2008
Messages
17,923
First.
Compression and spark tests.

One of the top posts in the forum is a post from FrankA
it's called a linc and sinc.
Do this.


Is the linkage operating both carbs at the same time??

From the description: it sounds like it's starving for fuel.

Replace the filter you already have with a clear one(jiggz) and check the hoses for soft mushy spots.

Outboardignition.com has test procedures for your motor.

​Pull carbs and check the reeds.
 
Last edited:

ol salty

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May 26, 2016
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Thanks, I had replaced the filter with a clear one already, linkage does operate both carbs at the same time. If I remember right the primer bulb felt like it was under pressure, couldn't even squeeze it, but don't have a problem when first starting up. I will double check that. I will run some of these test over the next few days, with all the rain we've had here in S Texas the humidity/heat index is crazy. Thanks again
 

tommarvin

Ensign
Joined
Nov 22, 2015
Messages
999
Idles fine , when you increase the throttle it misfires and will die if you don't back off the throttle.
Would this be trigger if you can't increase the throttle ? You could do a resistance/Dva check on trigger too.
 

Jiggz

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Oct 23, 2009
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3,817
Thanks, I had replaced the filter with a clear one already, linkage does operate both carbs at the same time. If I remember right the primer bulb felt like it was under pressure, couldn't even squeeze it, but don't have a problem when first starting up. I will double check that. I will run some of these test over the next few days, with all the rain we've had here in S Texas the humidity/heat index is crazy. Thanks again


Where is the clear fuel filter installed or located with reference to the fuel pump?
 

ol salty

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May 26, 2016
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fuel filter is located about 5in to the toward the rear of the motor from the fuel pump. the stator tested at 640 ohms, so i took a shot in the dark and replaced the trigger, found one of the wires was smashed between the cdm mounting bracket. Now I'm having problems getting my timing set, I watched a youtube video which showed grounding all the plug wires(older motor before cdm's) but when I do that and connect my timing light I'm not getting my light to light up when cranking. I thought well maybe I screwed up something but when I install plugs and hook them up the motor starts right up, know my timing is off because I had to replace the plastic piece that holds the adjustment screw(cracked). I had the timing light grounded to the starter and hot to battery, plugs were grounded to solenoid ground. Anybody know what I'm doing wrong. I did pull my plugs, 1/2 seem to have normal build up on them, but 3/4 were clean. Sorry it took me so long to get back, thanks for the help so far.
 

pnwboat

Rear Admiral
Joined
Oct 8, 2007
Messages
4,251
Try grounding the plugs and timing light to the engine block or try a different timing light.

I've found that some timing lights will not work unless you have the plugs hooked up to the wires and spark plugs grounded to the block. By-passing the plugs and grounding the spark plug wire directly to ground may not work with some timing lights. If you see spark at the plugs, the timing light should work. If not, try a different timing light.
 

Jiggz

Captain
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Oct 23, 2009
Messages
3,817
Well, it runs so test the timing light while it is running clamp it on #1 wire. Does it light up? If it does, then most likely the timing light is working. Now do the timing again this time ground the spark plugs using bare copper wires wrapped around the threads twisted tightly and straight to the engine. Just make sure the plugs are a distant away from the plug hole to prevent fire breath.
 

ol salty

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May 26, 2016
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WhoooHooo, my old timing light wasn't working so I had bought a new one, wouldn't ya know it, defective, took it back and got another one. Purrs like a kitten now. Timing was right on. I was able to check the timing with plugs pulled and plug wires grounded to the block. Thanks all, time to head down to Rockport.
 
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