3.0 LX Ignition Issue

Vegas Naturist

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Okay, this is strange... Background information, we're working on a 1997 3.0 LX serial number 0K179178. My boat was running good but stumbled on hard acceleration. Smooth acceleration was fine. I attributed this to a worn accelerator pump. I had the carb rebuilt by a marine shop here in town, and also asked him to check the tune. The boat sat unused since then (October) after the carb rebuild. It had less than a quarter tank of fuel. Earlier this month, we filled the boat (20ga fresh fuel added to about 8 ga then fresh fuel put in in September. We took the boat to the lake and it was very hard starting, ran very rough, wouldn't idle. I'm in the process of troubleshooting the issue. I have not contacted the marine mechanic who worked on the boat.

First thing I checked was ignition timing. I found the timing set at about 14 BTDC. I jumpered the two white wires to put it in base timing mode, so I could check base timing (spec is 1 BTDC). The timing didn't change. I checked all the wiring per the wiring diagram to be sure nothing was disconnected, corroded, etc. All seems okay. Checked again, timing did not change. This suggested the ignition module is defective. In truth, it is the original module, We're the original owners of the boat. I ordered a new module and pickup coil, module Sierra PN 18-5107-1 (maybe I should have bought OEM, but...) and coil Sierra PN 18-5108 from I-Boats. I installed both and reinstalled the distributor. Same problem! Jumping the two white wires and setting the base timing to 1 BTDC, disconnect the jumpers, timing stays at 1 BTDC. It still does not advance to 10 - 14 BTDC like it's supposed to. What am I missing? While possible, I have a hard time believing that both the old and new module are defective, with the same symptom. Any ideas?

John
 
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achris

More fish than mountain goat
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When you did the initial timing check did you also disconnect the shift interrupt switch wires and join them together? That may be what you missed.

P.S. Love the bottom line of your signature... :D :D :D
 

Vegas Naturist

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achris, if you're talking about the white wire with the green stripe and the purple wire, at the interrupt switch, yes I did. When I did, the engine died. When I closed the switch, the engine died. This led me to believe the switch is a normally open switch and closing it "interrupts" the ignition. At that point, I just disconnected it and left the wire "open". If I follow the purple wire on my schematic, it goes to a junction and branches off to the coil, alternator, electric choke, and to a canon plug. I had not checked the purple wire with a meter, but looking at the routing, it appears to be a hot wire. If the engine is not supposed to die when the green and purple wire are connected together, then I may need to explore the purple wire "downstream" and see if there is a problem...
 

achris

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Something not right here. If you have the wht/grn and a purple wire on the cutout switch, you have EST ignition. But it should not stall the engine when the wht/grn and the purple are joined.... Unless it's dropping the timing back so far that it's stalling.... Try this.... Wind the idle speed up to about 1000rpm. then jump the 2 white wires (on the dist.), then try joining the 2 shift cutout wires. Then go ahead and drop the idle speed to 750 and set the timing. If the timing has dropped back, then as you bring it up to the right place the engine should also run a bit quicker. If it does, just drop it back to 750 each time....

Alternately try advancing the timing to about 12 degrees BTDC without the jumpers, then do the jumper and joining of the wht/grn and the purple. Then set the timing using the correct method.

See how that goes. But if joining the wht/grn and the purple kills off the spark (verify with a timing light), something is not right, and it could be the problem source.

Chris......
 
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Vegas Naturist

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Thanks for the quick response! Yes, it is EST ignition. That's one thing I didn't check (loss of spark with the timing light). I'll try your suggestion this afternoon and post back the results...

And thanks Fun Times for the edit, I am sometimes dyslexic...
 

Fun Times

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And thanks Fun Times for the edit, I am sometimes dyslexic...
I'm a much better reader than a writer/speller and my grammar is even worse off. Oh well, I still like to try and help where I can. I was on the phone when I was skimming over your post and the 79 through me off for a second.:) Good luck.
 

Fun Times

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achris

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No conflict, FT, the manual and all the service bulletins agree, short the white dissy wires, unplug the cut-out switch and join the engine sides together, time the engine to 1 BTDC or ATDC (depending on the serial number and previous head gasket issues), set idle speed and you're done....

Also that video is for a 2008 model engine using the 'special' Merc shorting plug. Did you notice the engine didn't drop back to 'base timing' until he connected the flying lead to the 12 volt cable on the starter motor solenoid? Unplugging and joining the wires from the cutout switch does that.... Puts 12 volts (purple wire) on the wht/grn...

Chris......
 

Vegas Naturist

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...and an update. What I found was if I bypass the switch, I loose spark. If I jumper the white wires AND bypass the switch at the same time, I still get spark. Unfortunately I was pressed for time and just did some quick checking today. Where I was messing up was I had the engine running and was trying to bypass before I had the jumper installed. Tomorrow I'll have more time, and will try again to set base timing and let y'all know how it turns out. Also, that service bulletin does apply to my engine, so I guess I need to set the base timing to 1 ATDC?! Or does that apply only if there was a blown head gasket?

Thank you for the input. Sometimes just talking through it points out the errors... Since I started this thread with an engine running like crap, even when I get passed the ignition issue, I'll keep it active with updates until the engine runs top notch. It might help someone down the road.

John
 

fishrdan

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We took the boat to the lake and it was very hard starting, ran very rough, wouldn't idle.

This sounds to me like you still have a carb problem, instead of an ignition problem. You may now have an ignition problem due to the module/PU coil being swapped and timing, but once the timing is corrected, I wouldn't doubt there's still the issue you began with. All those symptoms could be attributed to too much fuel getting past the carb, float too low or fuel pushing past the needle/seat which could be a fuel pump problem. Or,,, maybe there's still an acc pump issue and the carb needs adjustments, that would give those symptoms too.
 
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Vegas Naturist

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Good morning Dan,

I have no doubt there are issues with the carb. I had them rebuild the carb and check the tune. I figured the tune was the easiest place to start, so that`s why I started there. You know, I`ve tuned that engine myself countless times without issue. This time I seemed to have let it kick my butt. Brain fart?

The carb issue to me seems like either fuel starvation or a vacuum leak. With it running, if I partly close off the choke, it runs somewhat better.

John
 
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fishrdan

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Yeah, no worries, I've been there before, fighting gremlins... So I take it that the boat wasn't run on the water after the October carb work?

With it running, if I partly close off the choke, it runs somewhat better.

That does sound like fuel starvation, have you played around with the carb's idle mixture and idle speed screws yet? A can of carb cleaner squirted around the carb base will help find a vacuum leak, listen for RPM change or bogging.

Also, I would remove the carb's flame arrestor, open the choke and (with the engine OFF) have someone slowly pump the shifter from idle to WOT,,, to see if the accelerator pump is delivering a nice steady shot of fuel into the carb. Try a fast pump too, to see if the acc pump shot is nice and steady when hammering the throttle. You will only be able to do this 5-10(?) times before the carb's bowl is sucked dry. If you don't have a second person to pump the throttle, remove the shifter linkage from the carb and manually open the carb, that's what I do.
 

fishrdan

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Oh yeah, I forgot, this is going to be a fun one as setting the timing is going to be difficult with carb problems,,, and dialing in the carb is going to be difficult with the ignition/timing problems. You may have to double-triple check things as you progress through the fix. IE: roughly set timing, tune carb, check/set timing again, tune carb again, etc. After you get everything running well in the driveway, you will need to follow up with a final tune of the carb settings when the boat is: -in the water -warmed up -idling in gear. Get it purring like a kitten when it's idling in gear....
 

Vegas Naturist

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Dan.

I just got back in from playing with Skinnydipper. Once i followed the PROPER procedure for setting the base timing, I was able to set the base timing, and once set back to "normal", it did advance to 14 BTDC. So that works now. The engine ran surprisingly well! Using my tach/dwell meter, I was able to set the idle to 750 RPM. I then played with the idle mixture screw till I was satisfied the mixture is good, rechecked the timing and idle speed, and all seems good at this point.

I reread the TSB that Chris posted, and my interpretation is that setting the base timing to 1 ATDC only applies IF you have had a head gasket issue, which we have not, so I set it to 1 BTDC as I always have. In reality, it's only 2 degrees so I'm not sure it is even an issue either way.

What is curious is that now I don't seem to be having what appeared to be a fuel starvation issue any more. This weekend I may have my First Mate help me double check the accelerator pump to be sure that's working properly. I won't be able to put the boat in the water for a final tune and shake down for a couple of weeks because of prior commitments, but 'll keep y'all informed...

Thank you for everybody's input. It sure helped!

Go Seahawks!

John

On a side note, I sometimes believe that there is a "Spirit in the Machine", and by letting someone else work on her (I typically do all the work myself), I angered that Spirit. I took me tinkering with her to appease the Spirit...
 
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achris

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I just got back in from playing with Skinnydipper. Once i followed the PROPER procedure for setting the base timing, I was able to set the base timing, and once set back to "normal", it did advance to 14 BTDC. So that works now. The engine ran surprisingly well!

Not surprised... If you set the timing to 1BDTC without it being in base mode, then you retarded it by about 14 degrees... Little wonder it ran 'poorly'.

Vegas Naturis said:
What is curious is that now I don't seem to be having what appeared to be a fuel starvation issue any more.

14 degrees of retard would make is feel like it was fuel starved...

Vegas Naturis said:
On a side note, I sometimes believe that there is a "Spirit in the Machine", and by letting someone else work on her (I typically do all the work myself), I angered that Spirit. I took me tinkering with her to appease the Spirit...

You have no idea how well I can relate to that belief... :thumb:

Real happy you have it sorted now.... Muladets.... ;)

Chris........
(currently in Moscow)
 
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fishrdan

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^^^ Yup, I'm with Chris, if the timing was retarded 14*, it would run like carp. Though, I question why it ran poorly after the carb rebuild, but before the ignition parts were swapped?

Electronic ignitions are pretty relaible and don't fail very often, so I wonder if there was an ignition problem, or if there is still a carb problem. One thing I learned long ago is to look at the last thing done, to see if that's causing a new problem. Or in other words, just because the carb was rebuilt doesn't mean it's working properly. The carb rebuild could have been successful, then the ignition puked, ignition repaired and timing was set incorrectly, then the timing set correctly, and now is all repaired, completely possible. But I would still keep carb problems on my radar...

Good luck and I hope it's repaired!

(As for the machine gods, the scenario I set up above is quite plausible... You had someone else fix the carb, so they broke the ignition for you... LOL)
 
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achris

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...Though, I question why it ran poorly after the carb rebuild, but before the ignition parts were swapped?

...First thing I checked was ignition timing. I found the timing set at about 14 BTDC. I jumpered the two white wires to put it in base timing mode, so I could check base timing (spec is 1 BTDC). The timing didn't change. I checked all the wiring per the wiring diagram to be sure nothing was disconnected, corroded, etc. All seems okay. Checked again, timing did not change. This suggested the ignition module is defective. In truth, it is the original module, We're the original owners of the boat. I ordered a new module and pickup coil, module Sierra PN 18-5107-1 (maybe I should have bought OEM, but...) and coil Sierra PN 18-5108 from I-Boats. I installed both and reinstalled the distributor. Same problem! Jumping the two white wires and setting the base timing to 1 BTDC, disconnect the jumpers, timing stays at 1 BTDC. It still does not advance to 10 - 14 BTDC like it's supposed to. What am I missing? While possible, I have a hard time believing that both the old and new module are defective, with the same symptom. Any ideas?

At this point I believe John set the timing at 1BTDC believing it was in base mode, but it wasn't. And here's where the timing got so retarded....

Mystery solved?
 

fishrdan

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I'm not sure if the mystery is solved...

From what John said, the carb was rebuild in Oct, then engine was running like carp a few months later (first try), and when he checked the timing it was at 14* which is correct timing.
I found the timing set at about 14 BTDC. I jumpered the two white wires to put it in base timing mode, so I could check base timing (spec is 1 BTDC). The timing didn't change. I checked all the wiring per the wiring diagram to be sure nothing was disconnected, corroded, etc. All seems okay. Checked again, timing did not change. This suggested the ignition module is defective.
The reason for replacing the ignition parts was due to the ignition not going into base timing mode, but he was using the incorrect procedure (which I have done myself), and the base timing mode problem happened with the new parts also. Thus swapping the parts and getting the timing off in the process. Now that the ignition is timed correctly, did this resolve the initial problem after the carb rebuild? I'm not sure of that.

He (we) will find out when he takes the boat out again, but something does not add up.

(Oh yeah, this is by no means an attack against you John or your mechanical skills, I've done the same/similar thing as I'm sure many on this forum have done...)
 
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Vegas Naturist

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Dan,

I didn't take your comments as an attack against my mechanical skills at all... Listen, I'm an ASE certified Master Medium/Heavy Duty Equipment Mechanic, have an Associates Degree in Automotive Technology, and have been working as a mechanic for almost 40 years. That doesn't mean I don't have the occasional brain fart. That's why I posted my question "what am I missing". I knew I was missing something and needed a "sounding board" to figure it out. I had the correct procedure, but was doing it in the wrong sequence IE bypassing the cutout switch BEFORE jumpering the dist. No offence taken!

The marine shop did two things, a tune and a carb rebuild. I always start with what was done last. I chose what seemed like at the time the easiest thing to check, the tune. In this case I had a 50/50 chance of finding the problem the first time round. Instead, I created a problem that didn't exist because of my brain fart. Surprisingly, once I got the timing sorted out, the engine ran like a champ. From here I can only speculate what happened. My gut feeling is, since the engine seemed to be suffering from fuel starvation (a symptom that can also be caused by improper timing), perhaps the new float needle stuck, or there was a small piece of trash left that partially blocked the float valve. and it finally cleared itself. Or, the Spirit was just angry with me...LOL. In any case, we'll see in a couple of weeks when I run it in the lake.

Again, thanks for the inputs, It's why this forum is so helpful.

John
 
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fishrdan

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Cool, I just wanted to make sure my comments didn't come across the wrong way.

Good luck out there!
 
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