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Discussion Starter · #1 · (Edited)
Hi All,

I'm researching and racking my brains as to why my 24hp 5424 won't stay running past 5 minutes at the dock. Here's what I did. Replaced 2 fuel lines from the tank to the water separator, and from the separator filter to the electric pump, replaced the water separator filter and the engine fuel filter. Filled the filters up with fuel before screwing them on. I've tightened the lug nuts out of both filters (figure of speech) and had to bleed the system a little at the fuel distributor. Got her to run, had to bleed it a couple times, but always at the fuel pump. After running for 5-10 minutes at the dock, we motored out the long fairway, got to the channel and she died (ran of out fuel). Got her to an end dock, bled the fuel distributor, again it would start, let it sit through various RPM ranges, shove off and within 5 minutes, running out of fuel again. I'm at a loss. :(

Help, thanks, Dave
 

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Discussion Starter · #2 ·
Just read the original owners manual on the subject of how to bleed the system. I didn't bleed the fuel filter.... First thing tomorrow after church.
 

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Most (if not all) tanks have a strainer on the bottom of the fuel pick up tube. symptoms you describe seem be just what I experienced some years ago before replacing the whole fuel system.
 

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Re: Universal no top RPM after fuel filter change

Well I got the beast to run after I bled the filter module, then the injector pump and even the injectors. Runs like a top, 600 RPM idle in gear all day long, purrs trike a kitten... Until I try to open her up and RPM stops at 2400 (cruise is 2300, max is 2800).

Now I know I'm going to get lots of hypothese but my bottom line is "if it worked as advertised BEFORE I changed 2 filters and 3' of fuel line... All of a sudden - it's not a rope wrapped around my prop shaft or bad fuel.

This is fuel related I'm very sure. Who else has been here? :eek:

Dave
 

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did you check the pick up strainer Dave? Exactly what happened to me until I finally (got my son to do it actually) found the strainer on the tube letting fuel through but with restricted flow.
 

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I've tried to understand this sentence but I failed :

"bottom line is "if it worked as advertised BEFORE I changed 2 filters and 3' of fuel line... All of a sudden - it's not a rope wrapped around my prop shaft or bad fuel."

but anyway... did the engine reach 2800 rpm under load just before this change? The most likely reason not to reach 2800 is a fouled prop, or one that is over-sized. The 5424 in my Bristol won't exceed 2500 rpm, but as performance is otherwise fine, I don't worry.

My bleeding procedure is as follows : (I have to start this with a full fuel tank to do step one, as I am using gravity at this stage)

1) Water separator - bleed until no air comes out.
2) Turn on ignition / electric lift pump.
3) Bleed at the fuel filter on the engine until no air comes out.
4) Finally bleed at the injection pump on the engine.

Even then, sometimes I get one bubble of air that makes the engine stall after five minutes running. Repeat the bleed at the injection pump.

The injection pump runs at very high pressure, so one small air bubble will stop it pumping at all.
 

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Re: Universal no top RPM after fuel filter change

Well I got the beast to run after I bled the filter module, then the injector pump and even the injectors. Runs like a top, 600 RPM idle in gear all day long, purrs trike a kitten... Until I try to open her up and RPM stops at 2400 (cruise is 2300, max is 2800).

Now I know I'm going to get lots of hypothese but my bottom line is "if it worked as advertised BEFORE I changed 2 filters and 3' of fuel line... All of a sudden - it's not a rope wrapped around my prop shaft or bad fuel.

This is fuel related I'm very sure. Who else has been here? :eek:

Dave
The highest probability is that when you reinstalled your 'filters' you pinched a gasket or O-ring during the installation and now under HIGH VACUUM as would be expected to develop in the fuel lines as generated by the lift pump when going toward FULL throttle position, there is a 'small' amount of air being 'sucked in' and past the incorrectly seated gasket or o-ring.
Rx: re-check the gaskets on the filter; and, if you have them install NEW and 'lubricate' the gaskets/O-rings with oil so that they dont 'deform' when you 'tighten down' on the filters.
If you removed any 'fittings' when replacing the filters carefully check the 'nut' on the fittings to be sure you havent 'cracked' one when retightening ... ditto, be sure that havent 'stripped a thread' on a nut.
 
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