1994 Mercury 150hp XRI EFI Black Max idle issues

[JOE54]

750 in gear, 3/8 naaaa dont think so , just make sure no air leaks

[digity]

Guess I should also have mentioned that I am going off of the tach on the dash, so it may not be super accurate. I am not going to do anything until after I fill up the tank and take it out next weekend. All in all after sleeping on it, I do believe it is 95% fixed but we will see. I'll report back after next weekend's test run.

[JOE54]

[digity]

So finally got a chance to put some fresh gas in and take it to the river. Right off the bat it started up and idled in the water, took it off the trailer and tied it to the dock, left it idling while I parked the truck, so far so good. Put it in gear, all good, mashed the throttle and took off like it always has, ran it wide open for a while, then down about half throttle for a while, then down to a no wake crawl, so far so good, then took it out of gear and it stayed idling, sweet it is fixed!

Not so fast it said! I repeated all the above for about 45 minutes to an hour and everything was fine, then on the way back I tried it one more time from the no wake crawl to neutral, BAM it died! It did start right up, but did not want to idle in neutral 400/500 rpm is what it wants to do and it would not stay running unless I bumped the handle throttle up to 750/800 rpm, I am able to get it in gear quickly and it will stay running at 750/800 in gear, but anything lower it will die.

So the miss is fixed, the fuel loss issue is fixed but it is apparently right back where this all started, so what in the world is left to replace or check?
Timing? ( I have not messed with any of the screws on all that throttle linkage)
Throttle Cable?
Idle Stabilizer?
Plug wires?

I mean good grief I have been through;
Switch boxes
Repaired ECU
New fuel/water filter
New fuel pump
clean the aft fuel pump screen
replace the fore fuel pump screen (the one in the hose)
rebuilt the diaphragm fuel pump
new plugs
new hose and primer bulb
took compression check 110 psi on all
ohm test the stater and trigger showed good

The motor runs strong, planes the 19' plate boat in a matter of feet, runs smooth and works as it should except for the doesn't want to idle in the water still and it does make it a little bit of a challenge to get on the trailer, you either come in hot, or it dies and then that can be an issue.

Suggestions?

[leonreno]

Remove idle stabalizer would be my next move, and it’s basically a free move.

[EuropeanAM]

^^^^ +1

Be sure to recheck all Sync-n-Link settings after you remove it.

Your engine can run consistently well WITHOUT the stabilizer (be sure to check at the switchboxes and verify that there is a JUMPER between the two bias terminals... white w/black stripe wire from inner to outer switchbox).

[digity]

Okay, now I have to learn how to check the link and sink. Yes it already has the jumper wire on it

[digity]

So I'll bring this back to life. Took the boat to a boat shop and they found 2 issues.
1. water in the VST, but funny thing was no water anywhere else because they check the tank, lines and filter.
2.The other issue was a broken reed that also had a loose screw.

So between the computer repair that did have bad drivers for fuel pump and injectors, the broken reed and water in the VST, I hope it is fixed. they did hook it up to the dyno and everything checked out fabulous. So between the computer repair, the boat shop repair and the parts I threw at it, i'm into it for about $1600.00, which overall I guess ain't too bad. If you want to play, at some point you have to pay. but I'm used to it, 2 boats, old jeep and a hot rod, LOL

We will see this spring how she does.

Thanks everyone for the input, direction and help.

[JOE54]

report back

[digity]

So, I finally got to take it out and run it through the paces yesterday and I am happy to report it runs as it should, idles in neutral at 950 to 1000 and in gear at about 750 to 825, going off the tach that is. It sounds a little quieter, doesn't blue smoke as much and appears to be getting a little better fuel mileage. Now lets just hope it stays that way. Thanks everyone for all the input.

[JOE54]

it was sick