2007 Yamaha 50hp 2stroke stuck in limp mode

[Gavinjones022]

have a 2007 Yamaha 50hp 2stroke
The problem I am having is it is stuck in limp mode and i can’t get it to come out. Ive changed the waterpump, thermostat, and heat sensor. When I start the boat up and put it in gear it will not go past 2000rpm it just hops up and stays there with no problem. There has been no alarms sounded and I have tried numerous of times.

[boscoe99]

Never heard of a Yamaha "limp" mode. What are you talking about?

[Gavinjones022]

Rpm reduction mode

[99yam40]

have you tested the alarm to make sure it is working?

timing light hooked to the different plug wires should show if they all are getting spark when the problem shows up.
and it will show if the timing is advancing as it should

[boscoe99]

If no alarm and no indication of a problem on the tachometer it is doubtful that it is in RPM reduction mode.

[Gavinjones022]

The alarm and tac work but they do not indicate anything.

[99yam40]

Well, if you are sure the alarm functions as it should and it is not coming in, then I agree the RPM reduction mode is not what is keeping the motor from running properly.
My BIL had a 50 2 stroke that would not pick up RPM.
when I tested it just backed into the water on the trailer, the motor would bog and die when the throttle was opened up in gear.
only thing I found wrong was the bottom carb main jet had some debris in it.
cleaned that out and it ran fine again

[Gavinjones022]

I found the problem. The piece that connect the throttle to the oil pump broke. I replaced it and now it runs great.

[99yam40]

I am glad it runs well now, but I do not see any correlation with the oil pump link and RPM loss.
Maybe someone can enlighten me on how it would.

oil pump should go full on when that happens, but I know of no reason it would limit RPM

[zenoahphobic]

Maybe the broken end was catching not allowing the throttle to continue opening.
Hard to see that full oil would be enough to alter fuel to air ratio enough, or that little extra oil could cause fouling of the plugs enough to make the spark weak.

[brian3006]

Maybe the broken end was catching not allowing the throttle to continue opening.
Hard to see that full oil would be enough to alter fuel to air ratio enough, or that little extra oil could cause fouling of the plugs enough to make the spark weak.

I bet this is it too. I have had this happen. The link got caught on the main oil line and would only open throttle quarter to half... Doubt the full oil made a difference. I had to replace some oil lines on mine and I disconnected the linkage and ran mine on full oil, plus 50:1 pre-mix (until the air bubbles were out of the line) other than lots of smoke, no difference..

[Gavinjones022]

The plugs were fouling out due to not getting any oil at all.

[99yam40]

The plugs were fouling out due to not getting any oil at all.

when the link comes off the oil pump should go full on, not off.
it is a fail safe state.
too much is a lot better than not enough

no oil would mean lost bearings and piston/cylinders

[Gavinjones022]

The pump was on off. When i put the new linkage on and gave it throttle it pulled it the opposite way of where it was sitting when not connected.

[zenoahphobic]

Well then we could conclude the engine was seizing with no oil.
Your reference to the plugs fouling because of no oil, I infer they were burning from excessive heat crusting and browning?