115 Mercury 4 stroke problems

kevins51825

Recruit
Joined
Jun 30, 2013
Messages
1
Two weeks ago my motor died on me at full throttle. Bulb was soft never started had to get towed in. Started in the driveway and ran at idle for 30 mins without missing a beat and bulb wasn't hard as rock but wasn't soft either somewhere in the middle. Put the boat in shop with a mercury mechanic and he found nothing wrong based on computer and running it in a tank. Took out the day I picked it up and ran like a dream approximately 2 miles down the river fished for a while then ran back without any issues. Today I took it out again and ran approximately 5 miles 10 mins or so at 5500 to 5800 RPMS up the river and stopped to idle over/around a ledge and when I throttled back up to get on plane it died again. Same as first time jerking and stopping then jerking finally dieing. Ran trolling motor for approximately 30 mins and still wouldn't stay running. TUrned over battery acted fine just wouldn't stay running. Pumped bulb and it got hard but went soft while trying to start. I thought it might be a battery issue so I hooked motor up to trolling battery and idled for approximately 1 mile no problem. Couldn't get into throttle or motor would die. Finally limped back to landing with trolling motor and motor cranked and put it on the trailer with motor. When I got home I cranked motor in driveway and ran for approximately 30 mins without a problem at idle speed. Removed hose after bulb and pumped tons of gas out when pumping bulb. So I am assuming nothing is blocking the line between motor and tank. Can a battery be good enough to start the motor but not to give it power when you go to WOT? Over heating? I am lost. I didn't get any overheating alarms on the water. Help please!
 

Bamaman1

Lieutenant Commander
Joined
May 15, 2011
Messages
1,895
Re: 115 Mercury 4 stroke problems

I suggest you go onto BBC Boards which is the bass boat website. Join the website. Then, copy this message on to the Mercury Engine question blog.

There is a fine independent marine mechanic shop out of Greenville South Carolina that closely monitors the website. He'll point you into a direction.
 

Faztbullet

Supreme Mariner
Joined
Mar 2, 2008
Messages
15,937
Re: 115 Mercury 4 stroke problems

Is the engine overcharging? What year? Does electric fuel pump quit when this happens?
 

Dmctruby

Recruit
Joined
Jul 31, 2013
Messages
1
Re: 115 Mercury 4 stroke problems

I have a 2010 115 Merc 4 stroke with similar issues. The dealer is just starting to look into the issue. Has already told me once he could not find any issues but when I ran it a few hours later the problem came back. This has led me to do my own research. I have come to find mercs suffer from several issues with the fsm, fuel supply module. There are several components to check. Pressure regulator, float switch and internal hoses (vacuum hose) have all caused issues. Note 2010 do not have fuel bulbs. All the fuel controls are inside the fsm. One key indicator there are fsm issues is if the foam air filter has been damaged by fuel. Fsm malfunction will cause excessive fuel vapors reaching the air filter. Not sure if this will apply to your year motor but there seems to be wide spread over several years
 
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