Suzuki df40 cranks but won't turn over

[timlovesfishn]

I ran my boat with a Suzuki df40tl efi 4 stroke the other day with no problems. Started and stopped multiple times without any issues. I brought it home and went to flush the motor and it wouldn't fire up. Cranks without any problem but just won't turn over. I don't believe it is the fuel since it has been used regularly lately and I have been keeping it filled up with high test. I checked all the basics first, the boats in neutral, kill switch is attached.. I've unscrewed the bolt at the top of the fuel rail and nothing sprayed out so I assumed it was the high pressure fuel pump and replaced it. I put everything back together and was expecting it to fire up but again nothing but the cranking of the starter. I doubt it's an issue with spark because I've sprayed the throttle body with throttle body and injector cleaner and it turned over briefly and than trying again after the cleaner burns up and the engine dies gives me the same result. I'm beginning to think that it might be a faulty switch. Probably the safety kill switch which I may attempt to by pass this evening to see if it will turn over. Any help or advice is appreciated. Thanks in advance.

 

[233mako]

If you are spraying cleaner or starting fluid directly into the throttle body and it fires up and runs for a second then it proves you have spark. The kill switch should not be the issue either since again .. it does fire up up indicating spark. The issue sounds like a fuel delivery issue. Again if it runs using starter fluid then the issue is from the carb to fuel line and back to your tank. I always troubleshoot by using a small external fuel tank and squeeze bulb to take any bad fuel, lines or water/fuel separator problems out of the picture. Connect that ext tank/line directly to the engine fuel barb and pump it up tight and give it a shot.

 

[timlovesfishn]

O.k. I am going to empty the fuel tank and lines tonight and start with new fuel. Thanks for the advice. I have however, gotten the engine to turn over and run but not well. It has a pretty rough idle and throttle response as well as some white/gray smoke coming from the exhaust . I was originally thinking it was just burning up some carbon but now I'm hoping it is just the gas. Thanks again

 

[timlovesfishn]

I was hoping that I resolved my issue permanently but of course it has come back to haunt me. Since I "fixed" the problem I ran the boat pretty regularly with no issues until about 3 weeks ago when after trolling all morning I shut the boat down and was attempting to do a drift or two before calling it a day. Well, after the first drift I went to start the motor and nothing. Couldn't get it to start and ended up beaching the boat and later towing it out.

Once home I started checking things that might be the problem. Originally I was thinking it was a switch, relay or ecu issue (because of a faulty multimeter I was using). Before realizing that I was receiving power at the harness going to the high pressure fuel pump I bypassed the lanyard kill switch, and than the engine mounted neutral switch. With none of these changing anything and finding current at the harness I went and replaced the relatively new fuel pump (covered under warranty). I was sure this was going to be the problem again. Unfortunately just another aggravating piece to the puzzle. Please help, I need to fish.

 

[timlovesfishn]

I forgot to mention that I also switched batteries as well as cutting off any corrosion I found on wires and connectors and replaced accordingly. I feel like I'm missing something simple at the same time I feel like there's nothing else to check.

 

[timlovesfishn]

Mechanic is backed up for a few weeks. Eagerly waiting for suggestions until they are available.

 

[timlovesfishn]

So, i took the newly replaced fuel pump out and tested it with 12v and it ran with no problem(As expected). So I'm back to an electrical problem somewhere that I haven't previously checked or Bypassed. I'm leaning towards an oil pressure switch, ignition key switch, crankshaft position sensor, camshaft position sensor. I'm just not sure if the last 3 would allow the starter to work but would possibly ground out the fuel pump.

Any feedback would be greatly appreciated.

 

[BOAT DOCTOR]

When you put the key in the on position can you hear the fuel pump run inside of the vapor tank for 3 to 5 seconds and do you have 35 psi of fuel pressure coming out of vapor tank if so I would also check the neutral switch by the control cable on the motor think it's a yellow wire with green stripe might try to bypass that if u got fuel pressure