mercruiser 4.3 died on the water please help

[CRLawrence]

Hey guys, I have learned a lot in a short amount of time on this page since I bought my first boat a month ago. The boat I purchased is a 2002 bayliner Capri 185 with a 4.3l merc/alpha one. The boat had a new long block put in it at the beginning on the summer and was ran once. I have put 21 hours on it while I have had it. I couldn’t be more happy with the boat until today. I hope you guys have some input. Here is the situation. Had the boat on the water at 11:00am, per usual it fired right up ran great, pulled some tubes around the lake, let the kids swim around, at 5:00 we decided to wrap up and head towards The docks. On our way in we decided to stop at the cliffs on our lake and let the kids play and jump off. I’d say we were WOT for about 3 minutes over to the cliffs. Dropped the kiddos off and I stayed on the boat and just cruises around at low idle in gear and out of gear to keep the boat away from the cliffs I would say 30 minutes in total. We then loaded the kids up, I killed to motor while the climbed the ladder, and fired it back up no problem and idled put away from the cliffs with no wake while the kids got settled. I then got into the throttle pretty deep and right before the boat came up on plane the motor died. This has never happened, I immediately push it back to nuetral and try to start it. It just turned over and over. So I’m freakin our and start tearing apart the seat to see if it was maybe a loose coil or if there was anything loose. Couldn’t see anything, checked all fuses. So now I think maybe it’s fuel related, maybe I lost the mechanical fuel pump. A nice couple came up to us after 10 min and offered to pull us in so I said absolutely thank you, we cruised to our ramp at 7-10mph, when we got to the dock I tried to fire it again and nothing.. I then went and got my pickup and trailer, fought it onto the trailer, pulled it out of the water and started unpacking and putting covers on and I just happen to think try it one more time, the darn thing fired right up. Do you guys have any opinions. Could the motor have been flooded from idling around at the cliffs for 30 min and then when I hammered down it couldn’t get enough air and choked it out? Only thing I did before this trip was change the water seperating fuel filter. Thank you in advance

 

[Tassie 1]

I would start by topping up the fuel tank and see how much it takes,
you have to do it anyway so might as well cross that off the list straight away as a possible cause,

Surprising how often that happens with a " new boat "
( G 'day )

 

[CRLawrence]

5.8 gallons of 91. I topped it off with 12 gallons of 91 before we went out. Most of today was spent at a little beach so not much fuel was used today. Appreciate your help. Being that it’s a mechanical fuel pump. Aren’t they kind of all or nothing. If it would have broke, would the boat have started again as soon at it was on the trailer?

 

[Faztbullet]

Did you knock the kill tether off when you got in it pretty deep?

 

[CRLawrence]

In the throttle deep. No switches got bumped but it was like a kill switch was hit, it died immediately. Just spooks me that after the tow and getting it onto the trailer it fired up like nothing was every wrong. I am going to take it and put it back in the lake tomorrow and see if the issue occurs again

 

[Tassie 1]

5.8 gallons of 91.. Being that it’s a mechanical fuel pump. Aren’t they kind of all or nothing. If it would have broke, would the boat have started again as soon at it was on the trailer?

Maybe just the different boat level in the car park etc etc but probably not the culprit anyway,
does sound fuel related though or the safety switch being knocked, as has already been mentioned,

Are you able to run the motor at home?

 

[CRLawrence]

I am going to pick up some muffs for the hose so I can do some testing tomorrow. Probably going to order a new fuel pump as well and possibly pull the pick up tube out of the tank and see if anything is wrong.. just hoping it isn’t spark related. Or electrical

 

[CRLawrence]

Anyone have any thoughts on a bad cam pos. Sensor? Maybe it could be the culprit?

 

[tpenfield]

Aren't boats fun

My thought is electrical . . . like a faulty kill switch. Particularly since the boat fired right up shortly after it would not run.

I would go through the ignition system's electrical wiring, making sure all of the connections are good. Clean up connections are needed.

Kill switch, ignition switch, shift interrupter switch, coil, distributor, etc.

 

[Faztbullet]

Is it a carb of MPI motor? Since it had a block change could be some loose wiring/connections. I would look at oil pressure switch to see if fuel pump come on...

 

[CRLawrence]

Thank you guys for your help. I have started going through the wiring, hopefully fuel pump with be in tomorrow. I may take it to the lake and see if the problem presents itself again. As of right now on the trailer, the boat fires immediately as nothing was wrong. Definitely don’t want to have to row but I’d like to be able to trust that it’s resolved

 

[QBhoy]

Oil pressure switch or choke failing like they usually do.