300X stutters at wide open and quit once

**Wild Bill** · 07-06-2020, 11:48 PM

Got an 02 300x that has been getting worse, when running wide open for a minute or two it will stutter only does it when giving it all she has got. It acts like it was shut off clean for a second, of course I lift and it starts running fine again and I can keep on driving. Did it today twice, once at 97 and again at 100 mph. The second time it quit and coasted to a stop, it had 40 psi on my fuel pressure gauge which is where I have it set on the regulator and the fuel squeeze bulb was hard. It didn't want to start it cranked and sputtered several times before it started and of course it ran just fine but I didn't go over 70 when heading back to the ramp. I am thinking it is electrical but am not sure where to start. I am not the electrical guy unfortunately, but if someone can point ne in the right direction it would be greatly appreciated. And no I don't have a ddt, I wish I did.

Thanks for any help, it is not cool when the engine quits at 100 it puts that knot in your belly that I am sure most of you have felt before. and I don't want to assume lake temperature trying to figure it out.

**mistah_max** · 07-07-2020, 05:32 AM

ok this is weird! i have a 02 300x that did the exact same thing last weekend. very interrested the see the replys you'll get! last time it shut off at 97mph and i got towed back being shure something bad had happen. plugs looked good everything was in place so i tried to start it up and after some time it started just like you. ran with my scanner on my lap the whole day at cruising speed with the family and it ran perfect. no codes, water temp aound 120, on the scanner. head temps is around 160 in the gauge, block pressure ok, primer bulb is always hard. i was suspecting i may have lost water pressure but no codes or alarm when it shut off.

**Wild Bill** · 07-07-2020, 12:31 PM

It has bin doing it for a while , at first i thought it was me because it happened so quickly but it is getting more frequent lately. Maybe it knows i have been having impure thoughts of replanting it with a 400 R if merc makes a N/A v8. That most likely wont happen because of the price.
Go out and let it eat, i bet it does it again. Going to give it a visual for loose wires and grounds and go out this afternoon, my wife will be along so i don't think i am going to run hard enough it make it happen.
Thanks in advance for any help

**mistah_max** · 07-07-2020, 02:31 PM

Originally Posted by Wild Bill

It has bin doing it for a while , at first i thought it was me because it happened so quickly but it is getting more frequent lately. Maybe it knows i have been having impure thoughts of replanting it with a 400 R if merc makes a N/A v8. That most likely wont happen because of the price.
Go out and let it eat, i bet it does it again. Going to give it a visual for loose wires and grounds and go out this afternoon, my wife will be along so i don't think i am going to run hard enough it make it happen.
Thanks in advance for any help

should be able to test friday. i have a spare crank sensor and map sensor ill bring with me. i have a rhinda techmate pro scanner so ill be able to monitor things out.

im still not ruling out a fuel problem tough...
im running a opti cowl with only one hole for rigging to go trough vs the alien cowl that has 2..everything is pretty tight in there..
and since the last time it shut off no codes or beeps where logged and it finally started up a while after, fuel starving could be the issue

**Wild Bill** · 07-08-2020, 04:45 PM

Ran fine yesterday only went 92 twice and was in it for less than a mile so it didn't have time to show up. Noticed some of the plug wires werent as clean as the should be so i cleaned them and dielectric greased them. Emailed Jay Smith, He went through my drag, and asked him what he thought. He told me to check the big multi pin plug from the ignition switch. Clean it , open the pins with an an exact o knife and grease it. Kind of makes sense, an intermittent loss of contact. Going to try that, good thing this boat settles down fairly sainley with a loss of power. Let me know what you find.

**Merc 2.5** · 07-08-2020, 08:46 PM

Maybe pull the plugs when it shuts off at high speed and see what they say ,, glad it just skips along and dont act stupid

**mistah_max** · 07-09-2020, 04:24 AM

Originally Posted by Wild Bill

Ran fine yesterday only went 92 twice and was in it for less than a mile so it didn't have time to show up. Noticed some of the plug wires werent as clean as the should be so i cleaned them and dielectric greased them. Emailed Jay Smith, He went through my drag, and asked him what he thought. He told me to check the big multi pin plug from the ignition switch. Clean it , open the pins with an an exact o knife and grease it. Kind of makes sense, an intermittent loss of contact. Going to try that, good thing this boat settles down fairly sainley with a loss of power. Let me know what you find.

ok thanks ill also make sure its clean.

as for spark plugs, i pulled them and they where a bit pale but ok. i had just shut off while being WFO so they looked fine to me.

**hondatech** · 07-21-2020, 05:39 AM

Try cleaning all grounds on relay plate. Main relay is grounded there and maybe intermittently losing contact.

**Dave Strong** · 07-21-2020, 11:09 AM

Originally Posted by Wild Bill

Ran fine yesterday only went 92 twice and was in it for less than a mile so it didn't have time to show up. Noticed some of the plug wires werent as clean as the should be so i cleaned them and dielectric greased them. Emailed Jay Smith, He went through my drag, and asked him what he thought. He told me to check the big multi pin plug from the ignition switch. Clean it , open the pins with an an exact o knife and grease it. Kind of makes sense, an intermittent loss of contact. Going to try that, good thing this boat settles down fairly sainley with a loss of power. Let me know what you find.

You get this fixed?

Dave

**Wild Bill** · 07-21-2020, 01:03 PM

Don't know yet, going to the river later this week to try. It hasn't done it on the smaller lakes I have ben to.

**2.5-21** · 10-04-2021, 08:07 AM

Any Updates on what caused this issue for both of you? I got one doing the same thing! Havent looked into it yet

**mistah_max** · 10-05-2021, 06:49 AM

Originally Posted by 2.5-21

Any Updates on what caused this issue for both of you? I got one doing the same thing! Havent looked into it yet

hey! i saw your PM. as weird as it is, i havent been able to duplicate the problem since. didnt find anything loose on the fuel or electrical side, engine ran fine the rest of the 2020 season and all of the 2021 season.. temps and fuel pressure are all within specs.

between the 2020 and 2021 season i changed reeds and had the injectors flowed but since it was a 1 time only episode for me i cant say that i've pin pointed excatly what happened on that day... i'd like to help out more but it has run flawlessly since that day.

**2.5-21** · 10-05-2021, 06:58 AM

Cool Thanks, I havent given mine a look at yet since it did it once, I will give it a check over before running it again and report back if I come up with something.....

**rgsauger** · 10-05-2021, 09:15 PM

That’s scary!!! My boat would toss your ass bigger than chit if you chopped the throttle at wfo. I might have learned that from a couple of hooks when I was learning to trim down before getting out of it. Never got wet but not far From it. Glad y’all are safe.

**Wild Bill** · 10-11-2021, 02:30 PM

Jay Smith told me to clean and expand the pins on the cannon plug on the motor. I did that and gooped it up with dielectric grease no problems since. Now my drag on my Ally XR02 started doing it, the dagon stinking pins on that plug ate too small to expand so i tried to squeeze in the female side. Need to have my wife cycle the key wile i wiggle the plug to see if i got it before i take it out. The pump sounds much better now. If it doesn't work i will bypass the plug and solder the wires. I know all about the hook did it once about 70 mph and made about a 9G turn. I know it would be instant death if that fuel pump quit at the speeds i like to drive it.