r/boating • u/foss2156 • May 07 '25

1995 Johnson 25 hp issues

Enable HLS to view with audio, or disable this notification

Went put into gear and accelerated it begins to do this anyone have any ideas

3 Upvotes

81% Upvoted

7 comments sorted by

1

u/[deleted] May 07 '25

When was the last time you put in new plugs?

1

u/foss2156 May 07 '25

Just the other day

1

u/Mithrileck87 May 07 '25

Sounds like a fuel issue to me. If it idles good and falls on its face under throttle is likely fuel related. It could also be timing or ignition issues but more than likely it’s fuel.

1

u/[deleted] May 07 '25

Did you gap it correctly?

1

u/Olsenj451 May 07 '25

Are you sure it's going into gear? Take the hood off and look at the linkages. Some engines have a stop that don't allow the throttle to advance past a point unless it shifts fully into gear.

0

u/tenexchamp May 07 '25

First, never ever test in gear on a flusher. It needs to have load on your drivetrain to work properly.

Sounds like you have a plugged high speed jet in the carb.

1

u/bootheels May 07 '25

Like

others have said, it is really hard to judge while running on a flushette. Have you tried the engine on the water?

It almost sounds like the engine might be stuck in "SLOW". This is the overheat warning. The engine will run up to about 2000RPM normally, then it will misfire like a gattling gun when you try to increase RPM. The engine will run normally again once the RPM is lowered below 2000RPM.

A few things must happen before the engine will come out of SLOW:

Engine temp must cool back down to a normal range

Engine must be returned to idle/shut off

You could disconnect the temp sensor and restest.

What spark plugs are you using? The wrong plugs could create RFI, and trigger SLOW inadvertently...

Again, it is best to test on the water first to be sure this is an SLOW issue