Michigan Sportsman Forum banner

1 - 9 of 9 Posts

·
Registered
Joined
·
1,200 Posts
Discussion Starter · #1 ·
Have a 125hp Mercury outboard. It's an 04. Today while out fishing noticed my hole shot was slower than normal. When returning I couldnt get above 28mph while I was wide open. This was about 4,000rpm's. Normally wide open I'm running over 5,000 rpm's and push over 40mph on a calm day. Going to change plugs tomorrow and go from there. Any ideas?
 

·
Registered
Joined
·
224 Posts
just went through some similar with a 2001 90 merc the motor never quit but would lose power after 30 seconds on plane....turned out the top carb float had a small hole in it and filled with fuel causing it to load with fuel...never fouled the plugs
 

·
Registered
Joined
·
9,081 Posts
Sounds like you dropped a cylinder
Look for a dry plug you may have a float stuck open or shut. Shut gives you a dry plug open floods it.
 

·
Registered
Joined
·
2,353 Posts
If it is a 4 stroke fuel injected you have clogged fuel injectors. I would put money in it. I have the same year 115hp and experienced the exact thing that happened to you. Basically your fuel line has been broken down by the ethanol gas and it clogged the fuel injectors. It costs about $1,000 for a shop to replace the injectors and all your fuel lines.

You can do it yourself for less. Typically you will find the lower injectors are the ones clogged. Which cause loss of power bot hole shot and top end. You also will see a significant drop in your rpms.

Good luck.


Outdoor Hub mobile, the outdoor information engine
 

·
Registered
Joined
·
1,200 Posts
Discussion Starter · #5 ·
It's a 2 stroke and I have treating it with Stabil/ethanol for the last two years. Hope it's not all that, but will see.
 

·
Registered
Joined
·
2,353 Posts
If it is a two stroke carberated motor then most likely it is carb related. Many times the needles for the floats will go bad. I had similar scenario on a 25 hp. Basically there is blockage within the carbs
a also it never hurts to clean or replace any fuel filter or filter screen.

Even if you have been treating it still inspect you fuel line going from the tank to the engine.

Outdoor Hub mobile, the outdoor information engine
 

·
Banned
Joined
·
4,684 Posts
Check for bad coil. If you have a bad one, then that cylinder will bog down the others. Easy to troubleshoot. Seen it many times.

Outdoor Hub mobile, the outdoor information engine
 

·
Registered
Joined
·
11,851 Posts
If it is a two stroke carberated motor then most likely it is carb related. Many times the needles for the floats will go bad. I had similar scenario on a 25 hp. Basically there is blockage within the carbs
a also it never hurts to clean or replace any fuel filter or filter sceens

Outdoor Hub mobile, the outdoor information engine

I found out I had a ton of junk in my screen....

Pretty sure my jets are clogged up too...What kind of fuel pump do you have?
 
1 - 9 of 9 Posts
Top