ALL_IN!

iTrader: (1)

This is a one month old boat to me, so history is not so clear.

Situation: The boat starts fine on the trailer, we travel a couple of miles on plane - boat runs great. We stop for some socializing - maybe 1-2 hours. Get ready to leave and no start. Engine cranks fine, but engine doesn't light off. So, we put jumper cables on from my buddies boat. After about 30 secs of charging the boat starts right up and runs fine.

This happened Friday night. On Saturday, bought 2 new batteries (as I didn't know the history of the original 2). Boat ran and started great all day Saturday. Then Sunday, see above.

Because the boat will start with jumper cables leads me to believe this is an electrical issue. I am using my jumper cables from the connector in the cockpit (2000 Fountain Fever 270).

Get it home and put it on the hose. Throughout my diagnosis time, the boat was started approximately 6-8 times, and it started great each time.

• B+ on alternator reads 14.1 volts off idle (1500 rpm)
• B+ on battery reads 13.7 volts off idle (1500 rpm), so I do have some voltage drop.
• Voltmeter on dash reads a little over 13 volts at WOT.

I cleaned and tightened both B+ and ground connections between the alternator, starter, and battery during this process and still have the same voltages. (connections were not so bad, really)

Because it cranks so well, and starts off of a jump, I'm a little baffled.

Any thoughts???

Thanks.

Dave M

What about the main ground on the back of the engine block?

ALL_IN!

iTrader: (1)

Duh! I didn't check that, Dave.

I'm on my way to Cincy for meetings tonight but will try to check that next.

I'm losing about half a volt somewhere. Its got to be basic.


What about 14.1 volts at Alt B+ I'm used to seeing 14.4v on cars and this is basically car engine electronics. Should I rebuild Alternator too to get 14.4 or is this enough?

supercat

You said boat cranks, does it crank normal speed or is it slow like drained battery? It may be an electrical issue if you are playing a high wattage stereo and draining battery but other than that cold start/warm start shouldn't matter if you have a bad connection.
Not sure about the jumping engine but these are prone to vapor lock on a very hot day after a good run then sitting for an hour. It may be that after you crank for a while then take the time to put on jumpers that it was getting fuel. My hp 500 efi does this on very hot days.

ALL_IN!

iTrader: (1)

The engine cranks fine - no lugging.

We were running hard on the way to the beach - 60 mph (almost WOT). It has been hot here this weekend, 90+ degrees. However, when it wouldn't start Fri night, the ambient air had cool off and we sat for 1-2 hours prior to an attempt to restart.

I'm baffled because it does crank over very well.

I did consider vapor lock and the jumper cables a coincidence. Is it a reasonable thought as a failure mode?

stevesxm

doesn't this sound like the dreaded vapor lock issue ? and all thats happening is that the time it takes to dig out the cables and hook everything up simply allows everything to cool off ? i mean it takes 200 amps to crank that motor and only 2 amps to run the injection and ignition... if it was low voltage, the thing wouldn't crank at all before the ignition and injection stopped working...

blue thunder

Your kill switch might be a might finicky. It cuts out the ignition but allows cranking. This would assume the fact you could jump start it is a red herring and you just bumped the lanyard and it made contact again.

ALL_IN!

iTrader: (1)

I was getting ready to search for that info. I wasn't sure what the kill switch killed. I will definitely check that, especially when the problem happens.

What sucks is, as I said earlier, last night it started 6-8 times on the trailer.

ALL_IN!

iTrader: (1)

I agree (I'm an ex-ASE certified tech, so I'm not satisfied with what my meter and my mind are telling me).

Unfortunately, when this has happened, I'm getting quite pi$$ed - so my problem solving is a little weak at that moment). I also haven't had a spark tester nor a meter with me - that will change on the next outing!

Anyway, you are right - if it cranks, it should have enough power to the ECU to command the coil pack to fire.

supercat

Even though ambient air had cooled off, the engine compartment stays hot for a looooong time. And after the vapor lock has pushed the gas back to the tank (assuming you don't have a check valve) you still have to crank like you ran out of gas. Try running slow with hatch open slightly for a little while before shutting it off or running blower for a while after you shut it off and see if problem disappears. My guess is it will.