2003 25 hp merc 2 stroke impeller replacement

The Force power

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I'm not able to find that in there

That's what I'd think. However the timing mark remained static no matter what I did with the advance on the light (2 different lights). Bought a new one that's supposed to work with a2 stroke, but I can't see how it would be different. Going to have another crack at it next weekend. Doubt a video would be able to capture it.
"However the timing mark remained static" I'm not sure what you mean by that?
 

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The mark stayed at 8' or something on the flywheel, and didn't move w engine revs or by advancing the light. Very odd.
The advancing feature is for 4-stroke (can't use that) I also had a closer look at your earlier write up and yes the timing set up will be a static-timing (full throttle at cranking speed)
Basically you use the light only for it to verify set/adjust the timing at cranking speed & it ends up where ever at full throttle at running speed
 

nola mike

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The advancing feature is for 4-stroke (can't use that) I also had a closer look at your earlier write up and yes the timing set up will be a static-timing (full throttle at cranking speed)
Basically you use the light only for it to verify set/adjust the timing at cranking speed & it ends up where ever at full throttle at running speed
Thanks. Not sure why the advance wouldn't work (might be off with 1 spark/rotation instead of every other?). So yeah, seemed like the number of sparks kind of ran into each other, the light was constantly firing almost when the engine was idling, and much worse at higher speeds.

So the timing is set up with the engine cranking but off (and throttle either closed for idle or open for wot)? How do you keep it from starting?
 

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Thanks. Not sure why the advance wouldn't work (might be off with 1 spark/rotation instead of every other?). So yeah, seemed like the number of sparks kind of ran into each other, the light was constantly firing almost when the engine was idling, and much worse at higher speeds.

So the timing is set up with the engine cranking but off (and throttle either closed for idle or open for wot)? How do you keep it from starting?
Full throttle WOT, you'll have to jump the starter so it will crank (as now it in gear) Keep your legs away from the propeller or remove.
Disconnect the fuel-line!!! and you may want to have the Cylinder wall lubed with some oil
 

nola mike

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ll throttle WOT, you'll have to jump the starter so it will crank (as now it in gear) Keep your legs away from the propeller or remove.
Disconnect the fuel-line!!! and you may want to have the Cylinder wall lubed with some oil
Very helpful. I was thinking static timing by rotating to tdc and seeing where the mark was (but this is better since you don't have to accurately find tdc) . How come it doesn't work right with the engine running?
 

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Very helpful. I was thinking static timing by rotating to tdc and seeing where the mark was (but this is better since you don't have to accurately find tdc) . How come it doesn't work right with the engine running?
Hang on..... you do need to know where you TDC is(and it mark on the flywheel) before you do anything.
You can verify by stick a screw driver (if proper tool is not avail.) in the #1 cylinder and find the spot where it sticks out the most, this verifies if the key is not sheared and the flywheel is in the right position (likely otherwise it would not RUN at all or real crappy)
There should be a marks on the flywheel for TDC & ignition mark
 

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Hang on..... you do need to know where you TDC is(and it mark on the flywheel) before you do anything.
You can verify by stick a screw driver (if proper tool is not avail.) in the #1 cylinder and find the spot where it sticks out the most, this verifies if the key is not sheared and the flywheel is in the right position (likely otherwise it would not RUN at all or real crappy)
There should be a marks on the flywheel for TDC & ignition mark
Forgot to mention...........the timing light will flash when running in Idle speed very close to TDC when the RPMs increase the further prior to TDC
However unless you have a large enough test-tank you will not be able test/see this...do not do this running on a hose cooling!
 

nola mike

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Hang on..... you do need to know where you TDC is(and it mark on the flywheel) before you do anything.
You can verify by stick a screw driver (if proper tool is not avail.) in the #1 cylinder and find the spot where it sticks out the most, this verifies if the key is not sheared and the flywheel is in the right position (likely otherwise it would not RUN at all or real crappy)
There should be a marks on the flywheel for TDC & ignition mark
Yeah I have marks on the flywheel, no reason to think there's a sheared key. I was thinking of a points ignition where I could tell the position of the flywheel when the spark fires (when the points break). Obviously can't do that on cdi.
Forgot to mention...........the timing light will flash when running in Idle speed very close to TDC when the RPMs increase the further prior to TDC
However unless you have a large enough test-tank you will not be able test/see this...do not do this running on a hose cooling!
Well, that's what I've been trying to do with the engine running and on the water. Again, at that point the timing light reads a constant number regardless of rpm or if I change the advance setting on the light. Specs are 6' btdc at idle and 25' @ 5500 rpm. So actually engine would have to be at 5500 to check timing since this is mechanical (presumably centrifugal) advance.
 

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Specs are 6' btdc at idle and 25' @ 5500 rpm. So actually engine would have to be at 5500 to check timing since this is mechanical (presumably centrifugal) advance.
Yes your correct but you would need a large test tank/Dynamo
I would not concern my self with the timing mark at 5500 RPM however verify you're not passing the 5500 rpms @ WOT.
I don't know the static timing mark @ cranking speed, does the manual not tell you?
Someone will tune in and tell us :)
 

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Yes your correct but you would need a large test tank/Dynamo
I would not concern my self with the timing mark at 5500 RPM however verify you're not passing the 5500 rpms @ WOT.
I don't know the static timing mark @ cranking speed, does the manual not tell you?
Someone will tune in and tell us :)
 

nola mike

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Yes your correct but you would need a large test tank/Dynamo
I would not concern my self with the timing mark at 5500 RPM however verify you're not passing the 5500 rpms @ WOT.
I don't know the static timing mark @ cranking speed, does the manual not tell you?
Someone will tune in and tell us :)
Well, timing at idle is 6', so it should be 6' until it starts to advance I'd think. I do want to verify WOT timing though, since I think the screw has been messed with before.
 
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