150 Mercury XRI no power and hard start

[Nuckolsn]

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

The manual I’m using is for 150 efi serial 0Dxxxxx and up

My serial is 0g061997

Unfortunately all the service places in my area are booked months out as I’m sure is the case all over , and no one I know has any test equipment

[Nuckolsn]

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.

My pump is outside the vst maybe I’m missing something
I can move the trigger through its full range by hand
thanks again for all the replies I’m sure I’ll get it sorted eventually lol

[OnPad]

My 97 supermag is mounted inside. My 95 200 is external.
Check out Ronnie's post if external 36-39psi.
Your hot on the trail.
Hope you don't have to buy a tps, last I heard they don't give them away, $$$ if you can find one.

[Nuckolsn]

The TPS is very expensive but, cheaper than the ECU/ACU lol

Im not opposed to spending money, as it sits right now the boat is useless soooooo I have to fix it lol

[Nuckolsn]

I will also add that the last water testing was performed both with and without the idle stabilizer hooked up.
I’ve read elsewhere that that box can cause problems when it fails (obviously not my problem currently) but what is the general consensus here? Remove ? Leave it?

[OnPad]

I have mine removed, without any negative consequences.
Some people like to leave em on.

[25two.stroke]

Check all your fuel filters. Theres like 4 in that engine. One in the J hose under the vst, one big green one inside a metal round housing in the upper forward port side of the engine. Also I have seen those pumps fail...pumping just fine at idle and then as soon as it gets up to 2000 or so the pressure drops off to 20 lbs and motor runs like ass. Make sure your fuel pressure is good and then check into the tps for sure.
You are using the correct manual for that engine.

[Nuckolsn]

Did your timing need to be reset after removal?

[Nuckolsn]

Check all your fuel filters. Theres like 4 in that engine. One in the J hose under the vst, one big green one inside a metal round housing in the upper forward port side of the engine. Also I have seen those pumps fail...pumping just fine at idle and then as soon as it gets up to 2000 or so the pressure drops off to 20 lbs and motor runs like ass. Make sure your fuel pressure is good and then check into the tps for sure.
You are using the correct manual for that engine.

All fuel filters have been checked/cleaned/replaced
even the screens at the injectors
Fuel pressure is 34-36 psi at idle and also while trying to accelerate (which is the problem I’m having)

[OnPad]

I did reset my timing. I don't recall it messing up my idle timing to much but was only getting 19° up top, had to bump that up to 24° or 25°.

[25two.stroke]

I did reset my timing. I don't recall it messing up my idle timing to much but was only getting 19° up top, had to bump that up to 24° or 25°.

I always check the timing after I take them off. And I always take them off. Sometimes the timing is no different with them off and sometimes its way off.
I would be suspect of your tps next...I'm sure someone has a good used one you can get a hold of.

[OnPad]

I probably don't recall it changing at idle, cause I don't use a light for idle, I just set so it doesn't die, usually the trigger barrel ends up almost splitting the case halves.

[bullet123]

I have a lot of parts lying around for those motors. I dont know much about the efi systems because I run carbs. Send me a pic or part number of the TPS and I can send you one

[Nuckolsn]

I have a lot of parts lying around for those motors. I dont know much about the efi systems because I run carbs. Send me a pic or part number of the TPS and I can send you one

Thanks for the offer but I ruled out the TPS
turns out my wire workaround for the test harness was causing inaccurate readings
I am now able to get the full range of voltage

[OnPad]

Stuff to consider.
Check spark.
Retest electrical components. Bias, kill circuit, voltage regulators, s. box in and out, coils, trigger.
Leaking injectors.
Fuel pressure regulator.
Pulse pump leaking fuel back to engine.
Reed valves broken.
Check valve, or obstruction in fuel tank.
Set timing, checking on all cylinders. Could have defective flywheel.
Lower unit trying to seize.