Engine sputtering over 2500 rpm while towing a tuber.

[Shipman]

Finally found a fuel pressure gauge and plan to use it next time out. Can someone tell me if the plug on the alternator should be plugged in or left off?

[Shipman]

Sorry Justgary, as I said, I am not a mechanic and doing my best. Took a while to find a fuel pressure guage but finally found one yesterday. Just trying to get some help.

[Shipman]

The pressure tester manual indicates that I need to relieve the fuel system pressure before connecting tester gauge. Any tips on best way to do this?

[justgary]

56 minutes ago, Shipman said:

The pressure tester manual indicates that I need to relieve the fuel system pressure before connecting tester gauge. Any tips on best way to do this?

Just screw the gauge onto the schrader valve.  No need to relieve pressure as long as the engine isn't running.  Screwing it on will relieve the pressure....

[Shipman]

Thanks, I will report the readings once I get back out on the water.

[Lancecape]

Pressure check was 62 consistently. Took boat out for first time this season same problem. Not sure what to do next.

[justgary]

4 hours ago, Lancecape said:

Pressure check was 62 consistently. Took boat out for first time this season same problem. Not sure what to do next.

Different username, but that's OK with me....

A 2004 engine should have 3 Bar (~44 PSI) at all times when the pump is running.  62 PSI indicates a bad regulator or a clogged return.

[INCOPPNITO]

The solution is simple - Stop pulling tubers. 

[Lancecape]

Yeah. Had to create a new account in order to continue to reply. What should the pressure be reading? Also I assume that the regulator or return would need to involve a shop or is it something I can do?

[Bozboat]

Bakes Fuel Pressure Chart

 

you should be able to remove and replace the fuel pressure regulator.  

Edited May 31, 2022 by Bozboat

[Lancecape]

Looking back I see that it should be 44. Sorry I missed that. So that means pressure is reading high correct? Could that be causing the sputter?

[Bozboat]

You could pull a spark plug or two out and inspect and see if they are flooded with gasoline.   @ justgary mentioned High fuel pressure usually indicates a bad regulator or clogged fuel line (return line)

[Lancecape]

I'm sorry, I am confused. The. Chart boxboat supplied indicates that it is correct. If that is the case. What is recommended next?

Edited May 31, 2022 by Lancecape

[Bozboat]

9 minutes ago, Lancecape said:

I'm sorry, I am confused. The. Chart boxboat supplied indicates that it is correct. If that is the case. What is recommended next?

one or more of your fuel injectors may be clogged or in need or rebuilding.  The key symptom for fuel injectors,   boat seems to hit a wall, runs great up to a certain RPM/load and then just won't go any further or faster.  Based on the age of your boat, you should look into sending the fuel injectors out for rebuilding.

Also, what is the condition of the spark plugs, rotor, rotor cap, spark plug wires etc, in terms of when where they last replaced>

 

 

 

Edited May 31, 2022 by Bozboat

[Lancecape]

spark plugs, rotor, rotor cap, spark plug wires have all been replaced in the last 2 years.

[Lancecape]

My issue is always under load over 2500 rpm after about 10-15 minutes of running. Sputters and bogs down like it wants to stall.

Edited May 31, 2022 by Lancecape

[justgary]

39 minutes ago, Lancecape said:

My issue is always under load over 2500 rpm after about 10-15 minutes of running. Sputters and bogs down like it wants to stall.

Now I'm confused.  If your fuel pressure is 62 and you have an ECM that assumes 44 PSI, your engine will not run properly because it will inject about 35% more fuel than it needs to run.

What is your fuel pressure?

[Lancecape]

It was someone else in the string of posts that said it should be 44. The chart also in this string says it should be 58-62. My reading was 62

Edited June 1, 2022 by Lancecape

[justgary]

3 hours ago, Lancecape said:

It was someone else in the string of posts that said it should be 44. The chart also in this string says it should be 58-62. My reading was 62

Sorry, my mistake.  I had convinced myself that 2004 was the last year of 44 PSI....

[Lancecape]

So would the opinion be that the next thing to have checked would be the fuel injectors. Sorry for all the questions. Just trying to figure out a problem that I have been dealing with for a while. As I have mentioned, I am not a mechanic. Plugs, wires, rotor, cap, fuel filter have all been changed. Fuel pressure is at 62. Sputter happens after about 10-15 minutes over 2500 rpm while towing a tube.

[justgary]

10 minutes ago, Lancecape said:

So would the opinion be that the next thing to have checked would be the fuel injectors. Sorry for all the questions. Just trying to figure out a problem that I have been dealing with for a while. As I have mentioned, I am not a mechanic. Plugs, wires, rotor, cap, fuel filter have all been changed. Fuel pressure is at 62. Sputter happens after about 10-15 minutes over 2500 rpm while towing a tube.

Cap and rotor within the last two years means nothing.  I would at least lift the cap and take a peek underneath.  If you used an automotive cap with aluminum tower terminals, it may be dead already.  The carbon button can crack, condensation can build up inside, cracks can form, etc.  When in doubt at all (like right now), just get a new cap and rotor with brass contacts.  If it still runs poorly, check the plugs next.

[formulaben]

7 hours ago, justgary said:

I would at least lift the cap and take a peek underneath.  If you used an automotive cap with aluminum tower terminals, it may be dead already.  The carbon button can crack, condensation can build up inside, cracks can form, etc.  When in doubt at all (like right now), just get a new cap and rotor with brass contacts.

I hate to be a broken record here, but for sure do the above and REMOVE the rotor and see how the contact is.  I won't bore you with the story but after hours and $$$$ we came to find the perfectly-looking rotor had serious corrosion underneath where the contactor was.  Everything else was replaced but that was the culprit.

[justgary]

9 hours ago, formulaben said:

I won't bore you with the story

Awwww, please?  We love that story!

[Bozboat]

17 hours ago, Lancecape said:

So would the opinion be that the next thing to have checked would be the fuel injectors. Sorry for all the questions. Just trying to figure out a problem that I have been dealing with for a while. As I have mentioned, I am not a mechanic. Plugs, wires, rotor, cap, fuel filter have all been changed. Fuel pressure is at 62. Sputter happens after about 10-15 minutes over 2500 rpm while towing a tube.

what RPMs do you read at wide open throttle (no tube)?

[justgary]

While you have the distributor cap off, also look at the ignition control module on the plate under the cap.  If the white painted dot is not white any more (e.g. yellow or brown), the module has probably overheated and could be causing your issue.

(Image snitched from TeamTalk)