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Mariner 115 hp dies

chiefmc

New member
"My 1988 Mariner 115 6 cylinde

"My 1988 Mariner 115 6 cylinder will start and idle all day. It will run up to 1500 rpm no problem, but as soon as you try to throttle up above 1500 it will die. Occasionally you can sneak it past that point and it then runs great up to 5400 rpm. If you throttle back but stay above 1500 you can drop the throttle and it responds every time. It has acted this way since I bought the boat/motor. I've only had it out a few times, last time after rebuilding the carbs (which were perfectly clean and measured good for float height and needle drop, but I put all new in). Any ideas?"
 
"Hi Michael,does it make any d

"Hi Michael,does it make any difference if you squeeze the fuel bulb?idle mixtures lean? compressions ok? ."
 
Your carbs' idle mixture m

Your carbs' idle mixture might be set a bit too lean. Try opening each idle adjustment screw 1/4 of a turn and see if that helps.

Jeff
 
"I'll try making it rich b

"I'll try making it rich by a 1/4 turn and hope I can get back to the lake soon. I take it from your suggestions that it is still running off the idle jets until about 1500. I haven't done comp checks yet but hope to this weekend. I initially assumed crud in the carbs, then the spark advance control box (which I read some folks think should be discarded... Do you agree?). Thanks for your help."
 
"Try the carbs first. The tra

"Try the carbs first. The transition from idle speed to 1,500 is about the time they start to open.

Be sure to let me know how you make out!

Jeff"
 
The primary pickup timing is M

The primary pickup timing is MUCHO important-O.
Get the manual and do the link and sync.

The box you refer to is the idle stablizer. That can be safely removed. You only need it when you have a big wheel prop. (20+")
 
Another possibility is that th

Another possibility is that the high speed winding on the stator has gone bad. You can check the voltage at the switchboxes. The red or red/white stripe is the high speed winding. The blue or blue/white stripe is the low speed.
 
I have an 86 Merc 115 that was

I have an 86 Merc 115 that was having close to the same problem. I found the new gas we have was eating the seal in the two piece carb floats and it was filling the floats with gas. Easy fix get solid floats.
 
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