Mercury 3.0 EST no spark

[Yz229]

That is correct. I think compression was about 170 all 4, but very consistent.

I did order another cheapy ignition module on ebay before I thought of running out to O'Reilly's and picking up a generic one. It just came in today, so I could throw that in and see. Be nice to have a known good OEM to try.

Only way I could think the module that's in is in issue is if the timing advance isn't working, which I didn't even think to check. But even if that were the case, doesn't really seem that would be the issue in this case.

 

[Scott06]

That is correct. I think compression was about 170 all 4, but very consistent.

I did order another cheapy ignition module on ebay before I thought of running out to O'Reilly's and picking up a generic one. It just came in today, so I could throw that in and see. Be nice to have a known good OEM to try.

Only way I could think the module that's in is in issue is if the timing advance isn't working, which I didn't even think to check. But even if that were the case, doesn't really seem that would be the issue in this case.

Lack of full advance would limit your rpm and power potential not backfire.
you said it was running at 170-180 i think that should have a 140 f thermostat which engine should run 150 ish wondering if that is contributing to run on? Might richen up the idle mix screw maybe half a turn and see if it helps run on to fatten it up.
would defintely try the oem module as a sanity check as we are running out of options on this one…

 

[alldodge]

Only way I could think the module that's in is in issue is if the timing advance isn't working, which I didn't even think to check. But even if that were the case, doesn't really seem that would be the issue in this case.

If it was advancing or not, running on the hard would have no effect on running or dieseling

 

[Yz229]

Lack of full advance would limit your rpm and power potential not backfire.
you said it was running at 170-180 i think that should have a 140 f thermostat which engine should run 150 ish wondering if that is contributing to run on? Might richen up the idle mix screw maybe half a turn and see if it helps run on to fatten it up.
would defintely try the oem module as a sanity check as we are running out of options on this one…

I actually tried fattening the mixture, also thinking that this engine was designed for no ethanol and the fact that I'm at sea level, so would need a richer setting, but it didn't help at the time. It actually seemed to help slightly going leaner then 1 1/8th, but not much. I will try again with carb that's actually rebuilt.

Trying to think of anything else carb related that could be causing the issue. Everything looked good inside. Confused what the 2 check balls were for included in kit, but I think I figured out what one of them was for.

I have OEM module but it seems to be dead.

 

[Yz229]

If it was advancing or not, running on the hard would have no effect on running or dieseling

Yeah, kind of just guessing at this point. Usually pretty good at figuring out this kind of stuff, just hard time with this one.

Maybe it is just half tank bad gas. I did fill it up to full a week ago. I would drain it, but I have no where to put full tank of gas.

 

[Scott06]

I actually tried fattening the mixture, also thinking that this engine was designed for no ethanol and the fact that I'm at sea level, so would need a richer setting, but it didn't help at the time. It actually seemed to help slightly going leaner then 1 1/8th, but not much. I will try again with carb that's actually rebuilt.

Trying to think of anything else carb related that could be causing the issue. Everything looked good inside. Confused what the 2 check balls were for included in kit, but I think I figured out what one of them was for.

I have OEM module but it seems to be dead.

Usually check balls go up and down stream of accelerator pump one may or may not be used in well of accelerator pump, on the discharge side of pump there is a ball in the passage feeding the accelerator pump shot to the venturi nozzles. There is a metal T staked into the passage to keep the ball in there

 

[Yz229]

Usually check balls go up and down stream of accelerator pump one may or may not be used in well of accelerator pump, on the discharge side of pump there is a ball in the passage feeding the accelerator pump shot to the venturi nozzles. There is a metal T staked into the passage to keep the ball in there

Ok that's what I thought. I actually tried to get the T off, but was pretty solid in there so I just stopped. Figured it wasn't the issue anyways.

 

[Scott06]

Ok that's what I thought. I actually tried to get the T off, but was pretty solid in there so I just stopped. Figured it wasn't the issue anyways.

As long as u are getting good pump shot no issue

 

[Eric 3.7LX Alpha 1]

A fuel pressure gauge on the inlet to the carb will tell you if the problem is before or after the carb.

 

[Yz229]

Been out with Rona, so haven't had much chance to work on boat. Was thinking, how far out are the idle mixture screws adjusted on these? I know manual shows 1 1/8th, but I figure at sea level, old possibly watery gas I may need to go out much more to richen it up. Maybe this has something to do with the bog.

 

[Scott06]

Been out with Rona, so haven't had much chance to work on boat. Was thinking, how far out are the idle mixture screws adjusted on these? I know manual shows 1 1/8th, but I figure at sea level, old possibly watery gas I may need to go out much more to richen it up. Maybe this has something to do with the bog.

Old possibly watery gas drain the gas and clean out not adjust mixture screw …

take a sample of your fuel and let it is in a jar. You will see if this is the issue

 

[Yz229]

Old possibly watery gas drain the gas and clean out not adjust mixture screw …

take a sample of your fuel and let it is in a jar. You will see if this is the issue

Gas is definitely bad, especially since i just heard it was filled up back in early 2020 with ACN (worst in country). I knew carb was toast as well, so started to fiddle with that. Ended up about 1.5 turns out (forgot about fact gas is old), which actually runs pretty good and no dieseling as well. But was also noting factory setting is 1 1/8 out. Being E10 87 octane ACN even fresh, most carbs usually need to run a little fatter especially on main at sea level. Was thinking 1.5 out probably wouldn't even be far out even with fresh gas, but was curious where others ended up. Haven't messed with a 2 barrel this size since like 1999.

Would be dumping gas regardless, but it's full tank and have no where to store at this time. Trying to figure that out.

 

[nola mike]

Gas is definitely bad, especially since i just heard it was filled up back in early 2020 with ACN (worst in country). I knew carb was toast as well, so started to fiddle with that. Ended up about 1.5 turns out (forgot about fact gas is old), which actually runs pretty good and no dieseling as well. But was also noting factory setting is 1 1/8 out. Being E10 87 octane ACN even fresh, most carbs usually need to run a little fatter especially on main at sea level. Was thinking 1.5 out probably wouldn't even be far out even with fresh gas, but was curious where others ended up. Haven't messed with a 2 barrel this size since like 1999.

Would be dumping gas regardless, but it's full tank and have no where to store at this time. Trying to figure that out.

The exact idle mixture is determined by your carb, and your boat. Regardless, idle mix isn't affecting your running problems once you get going

 

[Yz229]

Hi everyone,

Back at troubleshooting. Had my 1 year old in ICU and my 3 year old not much better. They are doing ok now!!

Back to the boat. Fuel looks fine, no water. Smells fine.

Decided to check timing advance. Nothing. It's 1BTDC before top dead center even while revving up. Followed the service manual instructions on checking. Could it be the new module I put in?

 

[Scott06]

Hi everyone,

Back at troubleshooting. Had my 1 year old in ICU and my 3 year old not much better. They are doing ok now!!

Back to the boat. Fuel looks fine, no water. Smells fine.

Decided to check timing advance. Nothing. It's 1BTDC before top dead center even while revving up. Followed the service manual instructions on checking. Could it be the new module I put in?

Yes especially if aftermarket seems to be common issue going in and out of base mode

You won’t make power with out any advance

 

[Yz229]

Took it out yesterday to see what it would do. No power, wouldn't rev past 2500 RPM's.

Tried 2 modules and it was the same. Anything else I should be looking at?

 

[Scott06]

Took it out yesterday to see what it would do. No power, wouldn't rev past 2500 RPM's.

Tried 2 modules and it was the same. Anything else I should be looking at?

Were the modules from the same supplier? So you are able to get it in base mode and set initial timing, but the timing doesnt advance past 18 deg BTDC? I think you should be 24-26 or so total at 2800 or so rpm.

Do you remove the jumper to put it in base mode? seems to be locked in base mode

 

[Yz229]

I put in base mode per directions in service manual, which has you jumping the two wires on dist, and bypassing shift interrupt. I set to 1* BTDC.

Once I take unhook wires on dist and put shift interrupt back it's still at 1* BTDC (should be 12* BTDC with advance at idle). When I rev it up, it has a hard time and timing is still at 1* even at 2,000RPM or so.

I've tried OEM module, cheaper O'reillys brand and another module and none of them are advancing. But I really can't think of anything else besides the module that would affect advance.

 

[alldodge]

Check advance with shift switch plug disconnected from dizzy

 

[Yz229]

Check advance with shift switch plug disconnected from dizzy

I believe that's the wire next to the two white wires that you connect to go into base mode? If I remember correctly, I had 12v on that.

Let me try that later and see. Thanks!