150 Mercury XRI no power and hard start

**tlwjkw** · 06-06-2022, 09:50 AM

send me an email addy and i'll send ya tha manual in pdf..... jan. i've run tha regular buh8/buhw's for years (up to 'bout '99) without any problems whatsoever.. jmo.

**PanRonnie** · 06-06-2022, 10:49 AM

There was a service bulletin about digital ecu, s and non resistor plugs not mixing
Thought 94 was already a digital ecu
Manuel attached
Having the tps adapter harness is nice to have

**tlwjkw** · 06-06-2022, 05:35 PM

yeah, i heard 'bout a bulletin but never actually saw one.. parts list still show bu8h all tha way thru '99 for us production.. idk? jus know i ran hw's in all my 260's over tha years..

**25two.stroke** · 06-07-2022, 12:20 PM

Originally Posted by tlwjkw

yeah, i heard 'bout a bulletin but never actually saw one.. parts list still show bu8h all tha way thru '99 for us production.. idk? jus know i ran hw's in all my 260's over tha years..

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**PanRonnie** · 06-07-2022, 12:43 PM

Also did some google-fu
They mention inductor plugs on 88 and 89 engines
I assume after this it was standard

**tlwjkw** · 06-07-2022, 07:07 PM

key there is "replaced" with tha 4949.. that ecu was before my time with tha 260's (couldn't afford it when they did show) so never had a problem.. we ran 11350's with all kinds a chips from us1... that part 'bout tha '88 220 and 89 200 with certain ecu's is strange that those are tha only two mentioned?.. but it is Merc... sooooooooooooooooo.

some thought it was a "jay smith" (back in tha '90's) thing when it was first brought up (tha pro max stuff) many years ago..... we jus kept doin' what we were doin'...............

**25two.stroke** · 06-08-2022, 11:06 AM

Originally Posted by tlwjkw

key there is "replaced" with tha 4949.. that ecu was before my time with tha 260's (couldn't afford it when they did show) so never had a problem.. we ran 11350's with all kinds a chips from us1... that part 'bout tha '88 220 and 89 200 with certain ecu's is strange that those are tha only two mentioned?.. but it is Merc... sooooooooooooooooo.

some thought it was a "jay smith" (back in tha '90's) thing when it was first brought up (tha pro max stuff) many years ago..... we jus kept doin' what we were doin'...............

Also note the 11350A37 (and the A40 on BPs) require resistor spark plugs.
Starting in 1994 all the 2.5 race engines (supposedly, according to merc) needed resistor plugs due to the internal tps.
So, its not just a matter of it being an 849849 ecu, its whether or not it had the internal tps or that external one on the port side.
As far as the fishin motor 2.5s they only required resistor plugs when they went to tp the CDM style ignition. So somewhere 1999 to 2000 and later, even though they still used an external tps.

**OnPad** · 06-08-2022, 11:23 AM

Nuckolsn, you have any luck with your stator swap?
All this spark plug talk got me thinkin. You could pull yours after running engine, and see if they are soaked with fuel or dry?
Also your fuel pressure is a bit low.

**PanRonnie** · 06-08-2022, 11:36 AM

Let me add this

**OnPad** · 06-08-2022, 11:42 AM

Thanks Ronnie. I guess you can disregard my fuel pressure comment.

**tlwjkw** · 06-08-2022, 02:03 PM

jus givin' our experience.. we ran hw's in every efi motor with every ecu available we had from a factory "laser" inj. BP ('87 model, only one i've ever seen) and multiple horn injected BP's to multiple '91 ta '98 260's (think '98 was tha year tha 4949 came out) without an issue..

2.5 cdm ign came in 2000.............

**Nuckolsn** · 06-08-2022, 03:14 PM

Originally Posted by OnPad

Nuckolsn, you have any luck with your stator swap?
All this spark plug talk got me thinkin. You could pull yours after running engine, and see if they are soaked with fuel or dry?
Also your fuel pressure is a bit low.

The stator swap , as you probably already know lol, did not cure the problem.
I verified spark while the planing problem existed. The plugs have all been wet on every instance that they have been wet with fuel.

I also verified voltage at the injectors during the time that the motor is acting up.

What should the fuel pressure be during acceleration? It’s running about 34-36 psi at all times even during malfunction

**Nuckolsn** · 06-08-2022, 03:26 PM

I have also realized that my battery is not charging and I can’t seem to get the tachometer to work, I’m going to have to see what tests I need to perform on the rectifiers.

Im still suspect of the TPS I re tested it for voltage and I cannot get it to read more than 3.94 the fsm states 7.4 should be the reading at w.o.t

I have checked and can confirm that I am getting the full range of motion on the throttle and top butterflies are opening all the way, still yet it’s not passing as much voltage as the manual specifies.
I have also verified that there is enough voltage present coming from the ECU to the TPS , there was 7.9 volts present at the 3 pin plug

**25two.stroke** · 06-08-2022, 03:43 PM

If I remember there were two different tps used on lazer motors that had different voltage readings.
If you are sure your motor should be getting 7.4 v @ WOT and it is only getting about half that then there is definitely a problem and that would cause all sorts of lack of power. Good thing to do would be find someone with a digital ecu and a ddt to read it and plug it in and look through all the parameters to see if anything is way off

**OnPad** · 06-08-2022, 03:51 PM

Your fuel pressure is fine with a pump mounted inside the vst. I wasn't paying attention again!
Sounds like you have a good handle on the situation.
Make sure your trigger isn't binding up, high speed timing bolt should be hitting the stop.