MerCruiser 4.3 Fuel Problem (I think)

kylef

Cadet
Joined
May 17, 2021
Messages
13
Hi all, just a disclaimer before I present my problem - I am a first time boat owner and not very mechanically minded.
Two weeks ago, I purchased a Stingray 190RS bow rider which I would like to use for wakeboarding, skiing, tubing and just cruising the lakes here in New Zealand. When I went to look at the boat, the seller took me for a test drive. We were on the water for around 20 minutes, and other than needing to be cranked twice to start it, it ran pretty well. I bought it based on that and took it home. It's been parked outside, covered and secure for two weeks.
Yesterday, I pulled the cover off, gave it a vacuum inside, wiped the seats and dash and tidied things up. I reinstalled the battery, connected a set of duel flush muffs and put the water on. The seller showed me to give it full throttle for a second before trying to start it, which I did and it started after having to crank it twice (it was around 10° Celsius/ 50° Fahrenheit). I let it run for about 10 minutes and it ran fine. I started it twice more a while later in the day to show my son and a friend and it ran fine, I even gave it a bit of throttle to see if it smoked or spluttered but it seemed to run fine.
Today, my wife and I drive the boat to a lake an hour away from us, reversed the trailer into the water and then I tried to start it again using the same method, one second full throttle and then back to neutral, turn the key but it didn't crank over. I must have tried for 10 minutes over and over but she wouldn't crank over. She was turning fine but just wouldn't actually start, like there was no fuel. I got my wife to drive back up the boat ramp to where it was flat, tried again and after the third time, it started, so I switched it off and we went back down the ramp. After trying to start it three times, it finally started. I got her off the trailer, my wife parked the car and hopped in and off we went. We must have ridden for at least 15 minutes, with no issues, smooth as silk. I had it at quarter throttle, half, 3 quarter and full with no issues. I slowed down so my wife could take some photos and then set off again, slowly getting to full throttle and after being back at full throttle for around 15 seconds, it literally just cut out, like it had run out of fuel. I then sat there for around ten minutes trying to start it but again, it would turn over but not actually start. We eventually started paddling to shore while continuously trying to start it until it eventually started and I made a dash to get to shore but it died again. This happened twice. I kept my eye on the gauges, the entire electrical system didn't die, just the motor. I battled on and off until it eventually got onto the trailer and brought it home. I connected the flush muffs and it started second crank but died shortly after. This happened a few times before I gave up, put the cover on and called it a day.
To me, it seems like a fuel issue as it was trying to start, the belts were turning - it definitely didn't seem like an issue with the ignition, have electrician double check.
I don't have a lot of info on the boat. The motor says MerCruiser 4.3/V6 AlphaOne. There is a sticker with the Engine Serial Number OF065795. I know nothing about the year it was produced or if the engine is even original or if the sticker on top is showing the correct information.
When I bought it, the owner showed me a receipt for work done in February this year, with the following comment on it : Check for not going, no spark. Diagnose to be either distributor pick up or module. Locate new pick up and fit to distributor. Run engine and check. OK. Change engine oil and filter.
I recorded a video yesterday with it running fine, https://youtube.com/shorts/HJ7gX9sc2m4?feature=share and I recorded a video today of it battling to keep its revs up and eventually stalling https://youtube.com/shorts/vYALzGwYfGU?feature=share.

Could anybody please point me in the direction of what could be wrong or what I could check to discover what could be wrong. I'll be honest, this boat used a lot of our savings so I am not in a position to pay somebody to tinker around to find the problem and charge me a fortune, I'm hoping to find the problem, take it to someone and say 'Hey, that's the problem, what can you do.'
I hope somebody could please help.
Regards, Kyle.
 

tpenfield

Moderator
Staff member
Joined
Jul 18, 2011
Messages
18,149
Greetings and welcome to iBoats . . .

There are many possibilities, but a couple things come to mind that you can look into. It will be a process of elimination until you find the cause.

It sounds like fuel starvation, possible causes are. . .

- Fuel tank vent line may be clogged.
- Check valve at the fuel tank fitting may not be opening properly
- Fuel pump is failing
- Carburator is gummed up with old fuel

Those should be good to get you started on finding the issue.
 

Fun Times

Moderator
Staff member
Joined
May 16, 2009
Messages
9,126
0F065795 comes up as an 1993 4.3L ALPHA, TB4, W/PS, TWO-PC-Exhaust, WORO, (262 CID) (GEN II) Model number 443B1003S...

Here's a parts catalog for the engine, https://www.mercruiserparts.com/4-3l-gen-ii-2-bbl-gm-262-v-6-1993-1-1

Plus to add a few thing of what [U]tpenfield[/U] mentioned, maybe check the fuel filter for water or debris and if it's full, https://www.mercruiserparts.com/bam/subassembly/31486/1599/60

Check the fuel pump to see if it's running continually while the engine is running and/or cranking/turning over in case maybe there's a oil psi switch issues that helps run the fuel pump, item number 10, https://www.mercruiserparts.com/bam/subassembly/31486/1599/40
or any other fuel pump issues as well.

There may be a screen on the bottom of the fuel pump inlet .

Item number 4 ought to be a Carb filter screen/strainer you could try checking for debris if your carb is a CARBURETOR(MERCARB - 2 BARREL),
 

Grub54891

Admiral
Joined
Jun 17, 2012
Messages
6,147
Did you have enough fuel in the tank? if to low at the ramp the fuel pickup may have been exposed and not picking up fuel. Just wondering......
 

kylef

Cadet
Joined
May 17, 2021
Messages
13
I did a bit of digging and found that the fuel water separator had last been changed in 2013 and I also found a kinked hose. She seems to be running perfectly now.
 

poconojoe

Lieutenant Commander
Joined
Sep 10, 2010
Messages
1,966
Just as a note to someone new to the hobby...
Never run your boat out of the water without a water hose connected to it, not even for a few seconds.
You can easily do catastrophic damage to several parts.

I would immediately change out the impeller on any boat "new" to me and especially since you started it in the parking lot at the ramp.
No guessing when it comes to cooling. So much can go wrong after an overheat situation. It doesn't take much to destroy an impeller, exhaust shutters and other engine internals.

Also, broken pieces of impeller and exhaust shutters can cause blockages throughout the whole cooling system.
 

IanFS

Petty Officer 2nd Class
Joined
Apr 21, 2009
Messages
188
Just as a note to someone new to the hobby...
Never run your boat out of the water without a water hose connected to it, not even for a few seconds.
You can easily do catastrophic damage to several parts.

I would immediately change out the impeller on any boat "new" to me and especially since you started it in the parking lot at the ramp.
No guessing when it comes to cooling. So much can go wrong after an overheat situation. It doesn't take much to destroy an impeller, exhaust shutters and other engine internals.

Also, broken pieces of impeller and exhaust shutters can cause blockages throughout the whole cooling system.
I couldn't agree more. A friend of mine started his engine without muffs, the impeller was toast. Luckily all the bits were found.
 

poconojoe

Lieutenant Commander
Joined
Sep 10, 2010
Messages
1,966
Another newbie tip...
Never run your engine with the drive up in trailer position. Too steep of an angle can damage the drive's u-joints.
Whenever the engine is running, the u-joints are spinning.
 
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