2007 3L PRO XS 225 guardian mode @ takeoff

[Champdan57]

Advice welcome!

As always, thanks in advance for any replies

2007 mercury pro xs 225
serial#- 1B507757
model#- 1225P73HD
400 hrs

Engine had a bad miss @ idle, when trying to ‘fast idle’, and when putting into gear. Basically anytime a load was being put onto the engine. It would die 30+ times in a tournament day. Motor runs fine up top and cranks flawlessly.

Replaced reeds and the big fuel filter with the red cap in the VST tank. Some of the The carbon reeds were slightly frayed on the end. But it still Did not fix the problem.

So I sent the fuel/direct injectors and rails complete to be professionally cleaned. I was told they were pretty dirty but they cleaned up really well. Said there was evidence of water in fuel as well.

I drained all of the gas out of VST, cleaned it.
Cyphoned all gas out of tank, refilled with fresh fuel and sta-bil.
Replaced all the fuel line from tank to engine.
Rebuilt the pulse pump with a complete kit.
Installed the clean injectors w/ the rails.

Took to the river for a test run today, idles ALOT better. Can be put into gear without dying. Can fast idle etc etc.

Ran into another problem:

Every now and then when trying to take off, it will go into guardian mode and hit the limiter with alarm beeps every time the engine surges. It does it especially when power loading onto the trailer. This is an intermittent problem not all the time. Also once on plane, around 3800-4K RPMS there is a certain miss. It will just kind of shutter.

Ive got an all new, clean fuel system and new reeds.

Starting to wonder if the battery is weak maybe?

TPS?

Please help. Lol

[castforcash]

My old 2003 225 opti acted like that when the battery was bad.

[Champdan57]

Thanks. That’s my next step. I hope that’s what it is

[Savage]

Check the shift position switch.

[Champdan57]

After lookin at it I think that may be my issue. Will report back tomorrow after I run it. Thanks savage.

[EuropeanAM]

Agree shift position switch is likely the "Guardian Cause"... also suspect it's time to replace those plugs with properly gapped IZFR6J (.043-.044")

[Champdan57]

Thanks guys

Ran the boat with shift switch unplugged. Fixed the guardian mode issue. Will be replacing the switch.
It still cuts out and dies occasionally, but I noticed if I turn off all juice pulling accessories, it runs better. So replacing the battery too.


Now I’ve noticed an issue in the gearcase. It’s a stock torquemaster LU. While in neutral and spin the prop there’s a grating/grinding sound. Checked foot oil, no shavings or even discoloration. Went ahead and changed the lube. Propshaft seems to be true with proper runout and end play. Don’t know, maybe I’m just dreaming stuff up now. Any ideas?

[Savage]

What was the prop shaft run-out?