4.3 LX MerCruiser will not start!

[ScottieinNC]

Bayliner 2252 Express, 4.3 LX 6 cyl carbed Merc, have spark, gas should be good, I ran last month and had Stabil in it. Spark seems a little weak, but plugs in good condition. Kill switch is OK.<br />I have the flame arrester off, tried the proper starting procedures several times, no luck.<br />Starting fluid down the carb runs for about 5-7 seconds, then dies, no matter throttle position.<br />I have changed the water separator, so maybe air got in the fuel lines?<br />What do I need to look for?<br /><br />HELP! Going to be 82° tomorrow and want to take boat out tomorrow!

 

[Don S]

Re: 4.3 LX MerCruiser will not start!

First of all, get that starting fluid off the boat. Give it to someone with an old truck or tractor. Unless you just like destroying your engine.<br /><br />Now to your problem, When you try to start it, does it always start and run for a bit then die? or was that only when using starting fluid.<br />You say the spark was weak, have you ever changed the cap or rotor?

 

[DHPMARINE]

Re: 4.3 LX MerCruiser will not start!

If the problem started with the changing of the water/fuel separator,remove it and fill it with fuel,then reinstall.The electric fuel pump often cannot reprime the system.<br /><br />DHP

 

[Haut Medoc]

Re: 4.3 LX MerCruiser will not start!

It sounds like a bad fuel pump......<br />You need to check the delivery pressure...<br />Instead of starting fluid try pouring some gas in the carb....What happens?<br />Does gas squirt in the carb when you pump the throttle?<br />I would try a separate gas can & see what happens.....JK

 

[Don S]

Re: 4.3 LX MerCruiser will not start!

Are you having a "No Start" problem or a "Start then die after a few seconds" problem.<br />If it's the latter start and die, you probably have a bad oil pressure "SWITCH" (not gauge sender) that is not allowing power to the electric fuel pump. Check the wiring to and from the pressure switch (Item 5 below) it's located just above the oil filter housing on the block.<br />The system is designed to run the pump while the starter is engaged which pumps gas into the carb for starting, when the engine starts, the oil pressure switch allows power to the fuel pump to operate when the starter is disengaged.<br />Just hook a jumper wire across the 2 terminals on the switch and see if it will stay running. If it does, you need a new switch.<br /><br />

 

[ScottieinNC]

Re: 4.3 LX MerCruiser will not start!

Got it going! <br />The water separator was bone dry after I tried to start it a few more times. I carefully primed it with fresh fuel and the engine came to life after two more tries.<br />I warmed it up real well then changed the oil and filter.<br />Thanks for all the replies fellas! (made a mental note of priming separator for next time)<br /><br />Questions: Why no starting fluid for boat inboard engines?<br /><br />What can I do to help insure good starting in cold conditions with this engine? (get away from being "cold natured"<br /><br />Don your diagram is awesome, I appreciate that!

 

[Don S]

Re: 4.3 LX MerCruiser will not start!

What can I do to help insure good starting in cold conditions with this engine?<br />

Keep it tuned up, and keep the fuel filters clean (and full ) and get the choke adjusted properly. Any carbed engine is more cold blooded than EFI, just the nature of the beast.<br />Starting fluid can damage pistons, valves, etc. If you can't get it started on gas, then there is a problem somewhere. As you noticed, it didn't help your problem at all.

 

[ScottieinNC]

Re: 4.3 LX MerCruiser will not start!

Thanks Don!<br /><br />To the water tomorrow we go!

 

[DHPMARINE]

Re: 4.3 LX MerCruiser will not start!

Hope you start and warm it up before leaving the trailer.Rev it a bit ,also.<br /><br />DHP

 

[ScottieinNC]

Re: 4.3 LX MerCruiser will not start!

Hey DHP,<br />I start it in the yard either the day before we go, or that morning if there's time. I do start on the trailer before my wife pulls away with the trailer. Learned that the hard way a few times, and seen others make the mistake as well. Then they have to tromp all the way back up the ramp, and haul the boat (unpowered) been there, done that!<br /><br />Tidying up some wiring now, getting ready for tomorrow!<br />Scott

 

[olly]

Re: 4.3 LX MerCruiser dies after start

Re: 4.3 LX MerCruiser dies after start

Are you having a "No Start" problem or a "Start then die after a few seconds" problem.<br />If it's the latter start and die, you probably have a bad oil pressure "SWITCH" (not gauge sender) that is not allowing power to the electric fuel pump. Check the wiring to and from the pressure switch (Item 5 below) it's located just above the oil filter housing on the block.<br />The system is designed to run the pump while the starter is engaged which pumps gas into the carb for starting, when the engine starts, the oil pressure switch allows power to the fuel pump to operate when the starter is disengaged.<br />Just hook a jumper wire across the 2 terminals on the switch and see if it will stay running. If it does, you need a new switch.<br /><br />

Having the start then die problem- oil pressure switch terminals corroded. I jumped the leads wires, (oil full, oil press gauge readings normal), replaced coil and fuel/water separator. Start easily Runs fine for 2 minutes on lift (with water cooling). In water in fwd runs about 1+ minute at 1100 rpm then dies. Rapid throttle advance kills it quicker. (4.3lx 94 -3 year old spark plug wires- 570 hrs on motor, battery 5 months old. FUll tank of gas in Sept 08-ran hard skiing & cruising on the 1st 1/4 of this tank of gas-no problems. Then rapid throttle advance and stalls out.

 

[chiefalen]

Re: 4.3 LX MerCruiser will not start!

Please start your own thread. bringing back a 2 year old thread no ones, gonna see it.