silverbullet87

Did you see 4K+ rpms with that issue? I'd imagine what you are talking about would restrict rpms a lot more.

Bulb doesn't go flat. I ran it off an external tank straight to the motor with no changes. This was with a different bulb too, so I've eliminated everything on the fuel tank side.
The filter on the motor is clean.

I didn't swap the jets - they are the "original" or basically whatever was in there previously. I guess someone could have installed incorrect jets at some point but doubtful.

This is something I haven't messed with yet.

nevets

the shift interrupter switch is notorious to go bad due to the way its mounted.Just unplug it and see if that is the culprit. I chased this on my 225 for a while. Also check for free rotation of the timing base trigger under the stator. if it is not turning freely the coils on the stator have cooked off the "potting material"

silverbullet87

I've tested this and it is working as it should, but I've since unplugged it just to eliminate another variable. It shifts fine with it unplugged, so i'll probably just leave it unplugged anyways.

CNC Boater

nevets

OK if the thermostats are new and functional test the temp sensors, brown wires on mine. I had a stuck thermostat that was taking out one bank thru that wire

silverbullet87

The shift interrupter is a switch with a sprung button that rolls over a cam on the shift linkage. When you shift from forward to neutral the button is pushed for a split second and should cut one bank momentarily to make it easier to get out of gear.

I've pressed the button with the motor @ idle and it clearly cuts one bank, so I know it works. With the sensor disconnected it will never have the opportunity to malfunction while at speed, so I don't have to wonder if the switch has somehow activated and is restricting my RPMs. I disconnected it for testing purposes, and just didn't bother reconnecting it because the motor has no issues at all going in and out of gear without it. It's one less thing to worry about for now.

silverbullet87

The thermostats are new, and i'm not seeing any high temp warnings on the tach. Maybe the warning isn't working, but alll cyls are firing (at idle at least) so I don't think this is the issue. I've confirmed this with an IR temp gun over each cyl head, and I can actually watch the temps drop when the thermostats open. (i've also confirmed each cyl has spark / fuel in the bowls etc)

I'm starting to wonder if there is an air leak behind intake manifold. Would a leak there trigger the CEL? Or a better question may be, where is the sensor that triggers a fuel restriction / air leak CEL located?


I'm still looking for a Johnson / OMC mechanic in the PA / MD / NJ area if anyone has suggestions.

CNC Boater

silverbullet87

No problem - I appreciate you trying to help. This thing has been a pain in the ass.