240 EFI M1 Issues starting

[nenikol23]

I've been having issues starting the boat. It will crank but not start. Fuel pressure about 37psi at the valve.
When cranking, it just sounds dry like there is no fuel. Spark has been checked and is good.

Thoughts?

 

[Tim75]

I've been having issues starting the boat. It will crank but not start. Fuel pressure about 37psi at the valve.
When cranking, it just sounds dry like there is no fuel. Spark has been checked and is good.

In the process of checking components we discovered something odd. If cranking a few times, then disconnecting the positive on the VST tank to disable the pump, it will start up after 2-3 cranks. It will run for about 5-10 seconds, until it burns the leftover fuel.

As soon as the VST positive gets reconnected, the sound while cranking changes immediately, sounds like a dry crank (constant, no bucking) and it will not start.

The only thing I can think of is the fuel/air ratio is messed up.

Thoughts?

What year is your engine?

Meanwhile-
Fuel pressure. Set your gauge. Key to Run. What is the pressure? Key Off. How long does it take for the the gauge to drop to zero? Checking for stuck open injectors flooding the engine. Killing the VST allows the engine to clear itself of fuel.

Have you checked the compression lately? All plugs out, wide open throttle. Kill switch pulled.

 

[nenikol23]

Hi Tim75,

Engine year is 2000. Fuel pressure 37psi.
About 30 seconds to drop to zero with key going from on->off.
Just replaced the injectors.

Compression has not been checked lately but I checked about a year ago it was 130-135psi on all 6. (didn't use the boat since)

 

[ripcuda]

Based on your description... my first thought was flooding of the engine, like Tim mentioned. I had a flooding, hot-restart issue (same engine). Sent my injectors off to BrucatoFIS for servicing. 4 were leaking or out of spec, had to replace 2... runs so much better now.

So when you are getting a no-start situation after multiple rounds of cranking. Pull a couple plugs and see if they are wet or dry.
Also an inline spark checker is useful to ensure still sparking while cranking (and not starting).

Cheers!

 

[Tim75]

Hi Tim75,

Engine year is 2000. Fuel pressure 37psi.
About 30 seconds to drop to zero with key going from on->off.
Just replaced the injectors, but with used ones. (I know, not a good idea but that is the current situation). Supposedly came off a running boat but who knows.

Compression has not been checked lately but I checked about a year ago it was 130-135psi on all 6. (didn't use the boat since)

37psi is in spec for pressure. 30 seconds from 37psi to zero psi is good news. System is leaking down somewhere, but does not seem like injectors. When injectors leak, pressure drops almost instantly. Could be leaking back thru the pump or thru the regulator.

I pulled my injectors (from 2001 engine) and had them tested and repaired at a shop in West Palm Beach. At the time, it was $20 each. Engine ran much better after. $800 new from Mercury.

Check your bleed system hoses. Those are the small black hoses that run around the front half of the engine block. The hoses break at the ends causing vacuum leak and poor running.

As Ripcuda said, check your spark plugs after crank-no start. They should all be wet with gas. Additionally, any dry plug means that your are not getting any fuel or OIL into that cylinder. Check the injector connector (round, thumb size, starboard, down low) for good connections. 3 wires + common. 2 injectors fire at one time. No green connections allowed.

The dreaded TPS can cause flooding also. It can call for max fuel at idle and thus flood. Many threads here about checking it. Dreaded because of cost- ~$700 now.