175hp Mercury no power ??

[profisher]

I agree..eliminate things first before just randomly taking things apart. Like starting it on the hose and pulling plug wires one at a time to see if all are actually firing.

 

[bentley]

So tonight i pulled all the plug wires off one at a time tonight, everything seemed fine, i tried some evinrude/johnson engine tuner that you spray into the carbs and let sit, going to also run some sea foam though it this weekend, when i take it out to test it, i will check all the gas lines then too. hopefully it will be cleared up. Weird thing is, it starts up on the first crank and idles really good.
thanks for the tips

 

[bentley]

So tonight i pulled all the plug wires off one at a time tonight, everything seemed fine, i tried some evinrude/johnson engine tuner that you spray into the carbs and let sit, going to also run some sea foam though it this weekend, when i take it out to test it, i will check all the gas lines then too. hopefully it will be cleared up. Weird thing is, it starts up on the first crank and idles really good.
thanks for the tips

 

[Island Fish Lifter]

low speed stator fires differently than high speed stator at a different engine speed, also you have two switch boxes. Means one runs one bank of cylinders, and the other one runs the other bank. So unless you are checking spark on both banks, your efforts are useless.

 

[Island Fish Lifter]

the fact that it idles fine tells me I would be looking at a high speed stator issue. If it was a carb problem, most likely your problem would be at idle. But what do I know, Im just another blinking light on a screen

 

[Island Fish Lifter]

here is something I would definately have tried from the start; when you unit is under load and clearly losing power, engage your choke. If your engine speed picks up, then you probably have a fuel problem.

 

[salmonkiller01]

This^^^^^^^^^

My brother has the same vintage mariner and he just replaced his second stator in 4 years, I was out with him fishing went to head home and lost power to get on plane, it was his stator.

 

[bentley]

Well I pulled apart all 3 carbs tonight and rebuilt them, I think I solved my problem, When I pulled the bowl off one of the carbs and took the float out, and found that one of the needle valves wasn't working, the seat, where the needle valve sits in had backed off not letting the needle valve open, so I was running lean in two cylinders, pretty much running on just 4 cylinders, still have to give it a sea trial, but I'm pretty confident that's it!!!!

 

[pod god]

it will be the stator under flywheel,idles and sounds great until under load where the high voltage part is not working,replace stator and will be good to go ,I have done hundreds of these in merc motors

 

[profisher]

I just replaced the stator and trigger coils on my Yamaha 200 2 stroke. Had an random intermittent miss that would appear while throttling up onto plane. Throttle back, turn it off, start it up again and the problem would disappear. Could go a day or a week before it happened again. I started it up on the hose to flush it and could tell it was missing so started pulling plug wires to isolate a cylinder. Turned out to be 2 cylinders. I remember my now retired mechanic friend telling me that if I ever loose 2 cylinders it is a trigger coil. Since I have a 3rd motor torn apart as a parts engine I decide to just pull the flywheel and change out both the stator and the trigger coils. No sign of the problem in over a month. The only problem is I'm not sure if I have a dud trigger coil or stator. Will have to see if I can test them on the bench to find the right one to throw out.

 

[Island Fish Lifter]

I just replaced the stator and trigger coils on my Yamaha 200 2 stroke. Had an random intermittent miss that would appear while throttling up onto plane. Throttle back, turn it off, start it up again and the problem would disappear. Could go a day or a week before it happened again. I started it up on the hose to flush it and could tell it was missing so started pulling plug wires to isolate a cylinder. Turned out to be 2 cylinders. I remember my now retired mechanic friend telling me that if I ever loose 2 cylinders it is a trigger coil. Since I have a 3rd motor torn apart as a parts engine I decide to just pull the flywheel and change out both the stator and the trigger coils. No sign of the problem in over a month. The only problem is I'm not sure if I have a dud trigger coil or stator. Will have to see if I can test them on the bench to find the right one to throw out.

the good thing about stators etc is that an ohms test will usually tell a story. I use a DVA meter as well for testing stator outputs.

 

[profisher]

Thanks, haven't thrown anything out yet...will try and determine which one is bad when I get some time.

 

[Steelman]

My buddy had the same problem on a new merc.he phoned the mechanic and was told over the hone it was a coil issue.
The mechanic said the mercs are known for this issue and he has replaced dozens and dozens.
Merc knows of the problem but does not want to use different coils.
He replaced it with a different aftermarket brand and assured him it wouldn't happen again.
No issues again.