Cuts out at speed

[JimN]

No new wiring with the new pump. Maybe on newer models, this is a ‘98 boat. I did check the wiring for the pump as best i could. Thanks

I just re-read the whole thread and didn't see any mention of which engine is in this boat. What do you have? '98 still had some models with the pump mounted on the engine and if that's the case, I would remove the fuel line from the inlet and check the screen for debris.

How old is the fuel in the tank? Sitting fo a long time and ending up with bad fuel tells me this could be a fuel quality problem. Your fuel line should have a Shrader valve- you need to test pressure on the water, not on the trailer in order for the test to be valid- it needs to be under load. While you're at it, take a fuel sample by using the purge valve on the gauge to allow gas to flow out of the clear tubing into a clean, clear bottle. Let it sit for awhile and look at it- if you see water or other fine debris, you need to clean out the tank.

I saw mention of the fuel shutoff at the tank- make sure that's open and if it has a long fitting after it, make sure it doesn't have anything blocking it- you would be surprised by the stuff I have seen in fuel tanks.

Are you still accelerating noticeably when this happens, or are you close to top speed? At what RPM is it happening? If it's in the 3500 ±200 RPM area, remove the fuel pump

[Stevensc]

It has the GM 350 with throttle body injection. Pump is mounted on the engine. Pump is a rouund cylinder about 6 inches long and 1.5 inch diameter. Fuel is new in tank along with Sea Foam additive. Thanks

[JimN]

It has the GM 350 with throttle body injection. Pump is mounted on the engine. Pump is a rouund cylinder about 6 inches long and 1.5 inch diameter. Fuel is new in tank along with Sea Foam additive. Thanks

That's what I suspected and the reason I mentioned cleaning the screen- it's due for that and it should be checked periodically, anyway.

BTW- check the main fuel line for internal delamination. The line material made before '98 wasn't made for use with Ethanol. MC had a recall at one point- you could contact them or a long-time MC dealer to see if they have a copy.

[Stevensc]

OK, here we go again. I had a local boat shop work on this issue last summer. It took them weeks and weeks. They did change out the fuel pump (again) and all lines plus other stuff. Unfortunately they took so long i really didn’t have time to run it before winter storage. Guess what, after a $1,600 repair bill it still has the same issues. I am now thinking maybe it could be the ECU but have no knowledge in this area. Could the ECU be the issue? And to reinterate and update, it now runs great for usually 15 to 20 minutes and then starts cutting out and surging for a few seconds then back to normal. Will do this regardless for RPM’s. I’m pulling my hair out here!!!

[Trekbike]

OK, here we go again. I had a local boat shop work on this issue last summer. It took them weeks and weeks. They did change out the fuel pump (again) and all lines plus other stuff. Unfortunately they took so long i really didn’t have time to run it before winter storage. Guess what, after a $1,600 repair bill it still has the same issues. I am now thinking maybe it could be the ECU but have no knowledge in this area. Could the ECU be the issue? And to reinterate and update, it now runs great for usually 15 to 20 minutes and then starts cutting out and surging for a few seconds then back to normal. Will do this regardless for RPM’s. I’m pulling my hair out here!!!

I just skimmed the posts so I don't know if this was discussed or not. Just throwing this out as something to check. Recently I had an issue with my '05 X-10 that would sometimes just cut out. Turned out to be the kill switch that had an intermittent connection issue. Vibration or movement of the kill switch lanyard and it would cut out. Probably a long shot that this is your issue but worth a check.

[JimN]

OK, here we go again. I had a local boat shop work on this issue last summer. It took them weeks and weeks. They did change out the fuel pump (again) and all lines plus other stuff. Unfortunately they took so long i really didn’t have time to run it before winter storage. Guess what, after a $1,600 repair bill it still has the same issues. I am now thinking maybe it could be the ECU but have no knowledge in this area. Could the ECU be the issue? And to reinterate and update, it now runs great for usually 15 to 20 minutes and then starts cutting out and surging for a few seconds then back to normal. Will do this regardless for RPM’s. I’m pulling my hair out here!!!

What is their service warranty? If they try to weasel out of giving your boat high priority, I would get a lawyer.

If they can't find qualified people to repair boats, they need to tell their customers and let them decide if they want to take the risk of having this place do the work and they need to asses the abilities of their staff.

DON'T REPLACE ANYTHING! The last hands on it need to find the problem or send it to another shop that can diagnose it without replacing everything in sight. That's not diagnostics, that's just replacing parts and declaring "We fixed it".

[Stevensc]

Trekbike, thanks for the response. I did replace the kill switch but will double check my connections being as this problem has morphed from one thing to another. Thanks

Jim, I would normally agree with you but i don’t want to fool with the last mechanic anymore and the only MC dealer in the area says they won’t work on it because of it’s age. So if anyone knows if the ECU could be causing issues like this i would love to know. Thanks

[JimN]

Jim, I would normally agree with you but i don’t want to fool with the last mechanic anymore and the only MC dealer in the area says they won’t work on it because of it’s age. So if anyone knows if the ECU could be causing issues like this i would love to know. Thanks

So you paid $1600 and aren't going to hold them responsible?

Sure, it's possible but there are ways to test ALL of the sensors and the ECM and that should be done before any parts are replaces, as I wrote.

This is a '98, right? If so, it's definitely more simple than the newer boats and if none of the shop's techs have been doing this kind of work for more than a couple of years, they may not have worked on the older models and I'm not knocking these, I'm knocking the shop for not making sure their techs are trained. If they din'g know, they need to ask tech support or someone who does know- if they can't find the answers, they need to grow a set and admit it to their customers.

[JimN]

Where are you located?

[mtajpa]

Does the problem correct it self after setting? Might have someone loosen the gas cap up once it starts running bad. Could have a plugged fuel tank vent.
Just a thought.

[Stevensc]

Jim, the boat is near Hendersonville, NC.

Mtajpa, it corrects it self usually in about 30 seconds or less.

I have ordered a scanner from Bob at OBD diagnostic. Anybody familiar with them? He says it will check everything.

[Stevensc]

BTW, Jim, i agree with all you say about holding the shop accountable and I probably will talk to them (him) about it but there a some personal reasons i am not pursuing him more vigorously.

[JimN]

Maybe the dealer in Charlotte has a Tech 1 left over from the old dealer- if they do or if you can find one with the marine card, it will work. That's what we usd for diagnostics when your boat was new and before that.

[88 PS190]

When I did mechanic work for these situations our first thing was to use a separate tank of fuel with a fuel pump in it and a hose. We would completely bypass the entire factory fuel system and run it. If it ran we'd work on the fuel system if it didn't we would work on something else.

Cutting out at speed particularly suddenly like if you gradually increase at at a certain RPM it just falls off is usually fuel supply and it can be on a TBI boat where the fuel pump is "sucking" off the tank that a bit of junk can cause the fuel pump to boil the fuel and cavitate. So I would be doing a real good clean up in the fuel tank itself. This is BTW why higher pressure fuel systems always have a fuel pump in the tank, drawing a vacuum on gas makes it boil off.

[Stevensc]

Finally made some progress. Wired the fuel pump directly to the battery and engine never cut out so we can tell that something is cutting power to the fuel pump momentarily. Any suggestions as to what to look for? Is there a fuel pump relay? Any ideas greatly appreciated. Thanks