Hello all-
I am a software guy, non-mechanic, so please cut me some slack as I try to debug and communicate. My neighbor is a long time mechanic but hasn't had experience with this TKS or the electronic advance timing; he would prefer the carburetor was a simple mechanical one without TKS in play at all, for instance.
Brief history
Boat was short on power about a month ago. Neighbor replaced a spark plug, power back to ~4500 rpm or so.
Next weekend, I only got it up to 4000 or so, but noticed it occasionally would pick up or lose RPM without touching the throttle (i.e., a sudden surge to a higher rpm, or a reduction), but things still seemed pretty normal.
I left town for a couple weeks, and neighbor continued to debug; he found more odd behavior such as surging and changes in top RPM, as well as stalling out at idle and when shifting.
Following weekend, was stalling out when I tried to shift into gear. Idle seemed normal, but would try to die as I shifted.
Serial # is
1A335597
Recent / current symptoms
While I was gone for a few weekends, my neighbor saw
-low idle
-low rpm
-stalling out
-but also all normal (high rpm, normal idle)
In shared troubleshooting together this weekend, we've seen all of the above again.
Sometimes it stalls out when shifting into gear, sometimes it stalls out after returning to neutral, sometimes it seems to have power, sometimes it doesn't, and TKS at least on one occasion seemed to be engaged when I don't think it should have been (i.e., after engine warm, heard air hissing through its passage).
Things we've looked at and tried to validate
Fuel
We've pumped gas into a jar (through the engine) and verified that we don't see much in the way of debris or water
Volume seems ok (but we haven't measured pressure)
The filter at the top is clean as a whistle (but we haven't checked the upstream filter or tank).
Idle speed
Neighbor adjusted the idle speed and we had it around 650-700 baseline idle, saw same behaviors. Also kicked it up to 1000, still saw stalling out and such.
Interrupt switch / shift cable
These could both cause problems when trying to shift, as I understand it. Cable seems ok, and my neighbor isolated the switch (i.e., disconnected it) and we still saw the same behavior.
2 Barrel Carburetor / TKS
Neighbor was keying in on the TKS system. This normally does its thing when cold, and can be heard 'hissing' until engine warms up (I always just thought it was a random hose noise that went away after a few minutes of heating up before we started researching).
So we 'bypassed' the TKS by disconnecting it and 'mostly' closing the air passage that TKS is meant to open and close depending on temperature.
It seems that we have the same sporadic idle stallout, and/or stall when shifting, etc even when TKS isn't engaged.
Spark plugs
One was replaced; but another went bad, according to my neighbor, who is suspicious of the distributor cap / TKS as well.
Distributor
Pulled this apart. The cap shows signs of corrosion on the contacts (?) inside the cylinder, and on the rotor (with the contact on top). The cap also shows signs of heat / fractures that don't look good. Note that this boat, while only in freshwater, did take on a lot of water early in its life (it was delivered with a leaking gasket, took on rain, and the bilge pump went south for a while).
Timing
My neighbor has adjusted the base timing (but I think only by his mechanic background, without putting the engine into base timing mode, etc).
Our best current guesses and next steps:
Our next step is to replace the distributor cap and the (rotor? is that the right name? The white/yellow piece with the metal contact on top) as its contact is also rusty / cruddy.
1
It appears that the advance timing is not properly functioning, so when the engine is put in gear, depending on the throttle, it is sometimes working, sometimes not, etc.
2
But it could also be that there's a sporadic fuel problem (like debris that are in the fuel tank or early filter, and occasionally clogging the fuel line)
3
It could also be that we didn't follow baseline idle timing properly and somehow that's contributing (but it seems to idle mostly ok, seems to have a problem when throttle is engaged or released).
My questions
Could we have messed up non-idle performance in trying to adjust the timing at idle?
Do I have the Thunderbolt ignition IV or V, or neither?? (Not sure what this even is but I've seen reference to it).
Assuming our idle / base timing is correct, what controls the advance timing? We think it must be electronic, and probably delivered by the black module.
(Model # Sae j1223).
Best guesses from the experienced forum watchers?
Advice & counsel?
Thanks for any constructive feedback.
I am a software guy, non-mechanic, so please cut me some slack as I try to debug and communicate. My neighbor is a long time mechanic but hasn't had experience with this TKS or the electronic advance timing; he would prefer the carburetor was a simple mechanical one without TKS in play at all, for instance.
Brief history
Boat was short on power about a month ago. Neighbor replaced a spark plug, power back to ~4500 rpm or so.
Next weekend, I only got it up to 4000 or so, but noticed it occasionally would pick up or lose RPM without touching the throttle (i.e., a sudden surge to a higher rpm, or a reduction), but things still seemed pretty normal.
I left town for a couple weeks, and neighbor continued to debug; he found more odd behavior such as surging and changes in top RPM, as well as stalling out at idle and when shifting.
Following weekend, was stalling out when I tried to shift into gear. Idle seemed normal, but would try to die as I shifted.
Serial # is
1A335597
Recent / current symptoms
While I was gone for a few weekends, my neighbor saw
-low idle
-low rpm
-stalling out
-but also all normal (high rpm, normal idle)
In shared troubleshooting together this weekend, we've seen all of the above again.
Sometimes it stalls out when shifting into gear, sometimes it stalls out after returning to neutral, sometimes it seems to have power, sometimes it doesn't, and TKS at least on one occasion seemed to be engaged when I don't think it should have been (i.e., after engine warm, heard air hissing through its passage).
Things we've looked at and tried to validate
Fuel
We've pumped gas into a jar (through the engine) and verified that we don't see much in the way of debris or water
Volume seems ok (but we haven't measured pressure)
The filter at the top is clean as a whistle (but we haven't checked the upstream filter or tank).
Idle speed
Neighbor adjusted the idle speed and we had it around 650-700 baseline idle, saw same behaviors. Also kicked it up to 1000, still saw stalling out and such.
Interrupt switch / shift cable
These could both cause problems when trying to shift, as I understand it. Cable seems ok, and my neighbor isolated the switch (i.e., disconnected it) and we still saw the same behavior.
2 Barrel Carburetor / TKS
Neighbor was keying in on the TKS system. This normally does its thing when cold, and can be heard 'hissing' until engine warms up (I always just thought it was a random hose noise that went away after a few minutes of heating up before we started researching).
So we 'bypassed' the TKS by disconnecting it and 'mostly' closing the air passage that TKS is meant to open and close depending on temperature.
It seems that we have the same sporadic idle stallout, and/or stall when shifting, etc even when TKS isn't engaged.
Spark plugs
One was replaced; but another went bad, according to my neighbor, who is suspicious of the distributor cap / TKS as well.
Distributor
Pulled this apart. The cap shows signs of corrosion on the contacts (?) inside the cylinder, and on the rotor (with the contact on top). The cap also shows signs of heat / fractures that don't look good. Note that this boat, while only in freshwater, did take on a lot of water early in its life (it was delivered with a leaking gasket, took on rain, and the bilge pump went south for a while).
Timing
My neighbor has adjusted the base timing (but I think only by his mechanic background, without putting the engine into base timing mode, etc).
Our best current guesses and next steps:
Our next step is to replace the distributor cap and the (rotor? is that the right name? The white/yellow piece with the metal contact on top) as its contact is also rusty / cruddy.
1
It appears that the advance timing is not properly functioning, so when the engine is put in gear, depending on the throttle, it is sometimes working, sometimes not, etc.
2
But it could also be that there's a sporadic fuel problem (like debris that are in the fuel tank or early filter, and occasionally clogging the fuel line)
3
It could also be that we didn't follow baseline idle timing properly and somehow that's contributing (but it seems to idle mostly ok, seems to have a problem when throttle is engaged or released).
My questions
Could we have messed up non-idle performance in trying to adjust the timing at idle?
Do I have the Thunderbolt ignition IV or V, or neither?? (Not sure what this even is but I've seen reference to it).
Assuming our idle / base timing is correct, what controls the advance timing? We think it must be electronic, and probably delivered by the black module.
(Model # Sae j1223).
Best guesses from the experienced forum watchers?
Advice & counsel?
Thanks for any constructive feedback.
