Cleaned carb and replaced shift cables, now engine dies after 1 min

[hangdogger512]

Ok, so I'm steadily going thru everything on my new boat project... its a 1992 GW Invader Rivera 220 deck boat with Mercruiser 4.3LX and Alpha 1 Gen 2 drive.

A few weeks ago I found a leak coming from the shift bellows, so I pulled the drive and replaced all the bellows and the lower shift cable. Then, when adjusting the shift system, I noticed that the upper cable had more slop than the recommended amount... so replaced it also. Shift system seems to be working now, but still shifting a little hard with muffs, so may need some more adjustment.

However, when I was checking the control cables, I noticed that the carb was looking a bit dirty, so pulled it and cleaned it while I had the throttle cable off anyway (I know probably a bit overzealous). It was filthy with sediment and carbon. Anyway, now when I start the engine, it idles very high for about a min (max of 2min), then sputters and dies. I've tried adjusting speed screw and mixture screws, but nothing helps... it always dies after about 1 min.

I am thinking about ordering the full overhaul kit for the carb (new floats, needles, accelerator pump, etc...) but hesitate doing that if in actuality it's just some adjustment or switch that I'm missing? Any thoughts?

Video 1: https://youtu.be/9OqYe5kJ9Jw

 

[alldodge]

Being a 1992 I'm thinking the motor should have an electric fuel pump. So you crank the motor, the fuel pump starts putting fuel in the carb and motor starts. Release the key and power is lost so it runs out of gas. So look at the oil pressure pump switch and make sure you didn't accidently pull the wire off. If wires are on it, jump the two wires together at the switch and see if it continues to run

 

[hangdogger512]

Video 2: (Longest time it ran yet, but still not smooth.) https://youtu.be/3lDGu1SRpWI

 

[Bt Doctur]

Fix the idle first because on a hose you could be killing the impeller at that high of a rpm

but still shifting a little hard with muffs,
On muffs it should be effortless

 

[hangdogger512]

AllDodge Thanks. I do have an electric fuel pump, and there is a single wire on the oil pressure pump switch. Which wires are you saying to jump and where?

 

[hangdogger512]

Bt Doctur I agree, but I haven't been able to fix the idle yet, as it dies too quickly. When I back out the speed screw, it dies immediately.

 

[Bt Doctur]

a base gasket leak will do the same this as having a vac leak Remove the cables first to set the adjustments, then attach the throttle cable

 

[alldodge]

Well its not sputtering and then dying like I thought so its not the fuel pump. Also the oil sender with only on wire is the oil pressure gauge sender and has no effect on the pump.

It 4:36 to 4:40 I see fuel drip off the accelerator pump. Then later you get it slowed down some and it starts bubbling up from the accelerator pump. So the float level is set to high. To adjust carb, start it up and have the throttle cable disconnected. Once you get it adjusted where it should be, then attached the cable making sure there is a very slight pressure from the cable keeping the carb closed at idle

 

[hangdogger512]

10/4, makes sense Bt Doctur and AllDodge I'll order a new gasket for the upper and pull it again to adjust the floats.

 

[alldodge]

If you don't tear the gasket taking it apart you can reuse it. There is no pressure inside, and it just keeps gas from slushing out

 

[hangdogger512]

OK, did the full rebuild kit on the carb anyway, and set floats... and that definitely helped the idle and starting issue... but it still dies after 40-60sec. Sounds great, idles perfect, then dies.

Any more thoughts?

New video:https://youtu.be/Hktlcea2jBo

 

[alldodge]

Your running out of gas. When you crank the motor power is feed to the fuel pump and it starts pumping into the carb. Motor starts, key is released which removes 12V from pump. Oil pressure comes up and closes contacts to power pump thru it. The issue is your not getting power either to the oil pressure switch, thru the switch to the pump.

Get a voltmeter and find the oil pressure switch. Turn the key ON and see if you have 12V on one side. If you do, turn key OFF, dis connect the oil pressure switch plug and jump between the two contacts. Now turn key back ON and listen for the fuel pump to be running

 

[hangdogger512]

Man, AllDodge you are spot on everytime. Thank you! Contacts were dirty... cleaned them, checked voltage... runs like a champ! I owe you a case of beer!

 

[alldodge]

Sounds great :thumb: