Issues: Power to starter and RPM restrictions

[JohnRennie]

I have a 2003 115 TXRB 2 stroke. I’m experiencing an inconsistent problem with getting power to my starter and RMP restrictions above 4400 RPM’s. I’ve cleaned my battery terminals, installed new batteries, new fuel pump and filters, rebuilt my carbs and cleaned the plugs. When the starter decides to not work I’m not getting any power at all to the starter – checked the starter terminal with my multi-meter while a friend cranked the engine. I have a feeling it may be due to an inconsistent short in my Neutral Switch Assy.

The other problem: I had the boat out all weekend. It started fine each time but my RPM’s were inconstantly restricted to 3700-4400. If I throttled up slowly and kept the engine below 4400 it ran fine, but if I punched the throttle or tried to run it wide open, the motor would shutter slightly, drop down to 3700 then would move back an fourth between 3700 and 4400. I took it easy all weekend but at the end of the day, I was able to throttle up to 5200, trimmed all the way out and it ran fine.

Since the problem is inconsistent, I believe the carbs and fuel systems may be ok and it could be contributed to an electrical issue… unless the high-speed carb adjustment is off… but I think if that were the case, the problem would be consistent.

I’ve read through many posts and found that the F115 may have 2 switches: shift position and shift cut. I think the shift position switch limit’s the RPM’s if it’s in gear and the ECU gets a crank signal. Anyone know if the 115TXRB 2-strokes also have both switches? I found the Neutral Switch Assy in the schematics but no other switch in the control box unless I missed it or if it’s under the cowling. From what I’ve researched, one or both of these switches may be shorting or it could be an issue with my power pack.

Lastly… if I can get my motor up above 4400 RPM’s and stay there, it runs fine – no RPM restrictions, but if I back down then reaccelerate the problem may come back.

I typically keep my engine below 4400 but I need to be able to run higher at times.

Any thoughts would be greatly appreciated.

[cliff mock]

Power to engine

I had a simular on my 115 2 stroke last year. New batteries, some time it would crank and some time not, it acted like a bad starter with a bad place on the armature. By chance I was working on it at the house, knew I had a full charge on both batteries. Hit the switch, and just happen to be looking back at the engine and seen smoke rise inside the well were the power cable from the batteries to the engine laid when the engine was tilted for trailering. After examination on the bottm of the cable the insulation had been rubbed and over a period of time the flexing of the cable had broken many of the stranded wires run inside of the insalation. Would have never of looked for that if I hadn't seen smoke rise. The whole time I would check and had 12 volts, but not enough good cable to carry the amps required to turn the starter. Don't know if this helps, but it was a experience.

[JohnRennie]

Thanks Cliff, I think I found the problem with power to the starter. It looks as if the wire connecting the starter to the solenoid had a short. We replaced it and so far I’ve had no problems starting. I still have an issue with power reduction.

I ran the boat with a buddy who just graduated from marine tech school. Of course, the engine ran perfect for the first couple hours then the problem finally came back. Something is happening to restrict the rev’s inconsistently. We had to pull the boat out due to a storm so he didn’t get much time to diagnose. He thought possibly an overheat issue so we tested the thermostats and they were working properly. The only time I get rev restrictions is as I’m coming to a plane… and the problem is sporadic… no consistency at all. I think it’s gotta be something electrical. A short or a bad ground.

Anyone have any advice as to where I should start looking?