Changed both fuel filters. Now engine won’t start. Now repaired!

Bruceflinch

Older Swabbie, Younger Boat
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Oct 6, 2023
106
Bay Point, CA
Boat Info
1986 340 Sedan. Twin 340 Mercruiser
Maintenance is harder when you’re old..
Engines
Twin Mercruiser 340 inboards
Dag nab it!
I replaced both primary and secondary fuel filters. Engine wouldn’t start. It did run before changing the fuel filters.

Remove both filters and fill them with gas. Still will not start. I repeated that twice.

Helpful hints anyone?
Thanks in advance.
 
I think you had another thread going - what did you end up replacing the non-screw on filter with?

Did the fuel leave the filters between tries (ie. why did you have to fill them twice)?

Silly question - do you have a kill switch that might be interrupting spark but not cranking?

I've got 2 screw-on type filters and mechanical fuel pumps. I've never had to fill my filters to have them start up immediately after replacing both filters...for what it's worth.
 
Maybe flooded the engines while cranking...let em sit for a while?
 
Check the seals on the filters. If you didn't get them sealed right, you're letting air in and you won't get fuel.
 
I think you had another thread going - what did you end up replacing the non-screw on filter with?

Did the fuel leave the filters between tries (ie. why did you have to fill them twice)?

Silly question - do you have a kill switch that might be interrupting spark but not cranking?

I've got 2 screw-on type filters and mechanical fuel pumps. I've never had to fill my filters to have them start up immediately after replacing both filters...for what it's worth.
I was able to find Fram replacement filter cartridges.

No Killswitch that I can find.


I can smell gas when I finish cranking the engine

Weird, the motor started from the fly bridge. So that starter switch was off. Duh
Ran for a few minutes, then stalled.

It does not want to start again.
 
I was able to find Fram replacement filter cartridges.

No Killswitch that I can find.


I can smell gas when I finish cranking the engine

Weird, the motor started from the fly bridge. So that starter switch was off. Duh
Ran for a few minutes, then stalled.

It does not want to start again.
Is your fuel line shutoff valve open?
 
Is your fuel line shutoff valve open?
I never closed it. Can’t see one to tell the truth.

I filled both filters with fuel. Motor starts runs for about three minutes and shuts off. I repeated three times.
Tomorrow I’m going to drain the primary filter to see if there is water in it
 
I never closed it. Can’t see one to tell the truth.

I filled both filters with fuel. Motor starts runs for about three minutes and shuts off. I repeated three times.
Tomorrow I’m going to drain the primary filter to see if there is water in it
Yeah since you replaced the filters, check the connections and whatnot real good. I had the same thing happen with an old canister type fuel filter. Turned out I didn't have it sealed properly when I re-installed.
 
The plot thickens…
The supplied gaskets do not seem to fit so well, in this starboard engine application. Wix.
Port engine worked after filter replacement.
The generator ran after filter replacement.
Generator is on the same tank as the starboard engine.
I am not finding a reliable source to get exact gasket replacements.
I've discounted of the possibility of too much water in the fuel tank since the generator runs OK out of the same tank.

I guess now I will disconnect the filter assembly and blow some air down the pick up tube to see if it is clogged.
I have surveyed for the possibility of replacing the entire filter assembly, of which I am considering. Shit!
 
The answer to my problem!
I discovered a cracked brass nipple, adding to the leak.. pretty sure I did that… argh
$190 Parts and 4 hrs of Boatyoga.
The filter on the left feeds the generator. Original,
Fram discontinued that model over 10 years ago.
filters are available but the correct gaskets are not.

The engine idle well and after warming it up, I was able to do a good oil change and filter

coolant change out next
 

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