4.3 liter Merc stalling after winter dormancy

[stanms]

I have a 1999 Mariah Shabah with a 4.3 Liter carbureted Mercruiser engine. Ran fine since new even after winterizing. This year I went to start her up after a long winter dormancy and she cranked up no problem. After a minute or so she stalls out. Seems to be gas starved. I can crank her right back up and she runs for another 45 seconds or a minute and stalls off again. Choke is fine, not sticking... I replaced the fuel/water separator filter & installed new plugs. Runs great a minute at a time... oh yeah... tried new gas too... it didnt help. Any help on this? I am at my wits end!!!

 

[Bondo]

Re: 4.3 liter Merc stalling after winter dormancy

Check the wiring for the "Run" circuit of the fuel pump......<br />The "Start" circuit seems to be pumping........

 

[stanms]

Re: 4.3 liter Merc stalling after winter dormancy

I have a schematic of the fuel system wiring diagram but I see no evidence of twwo separate circuits... Could you advise on how to check the "run" versus "start" circuits? Or provide a place I could look for this info? Thanks... Is it possible it is a fuel pump or carb float issue? Thanks for the response !!!

 

[Bondo]

Re: 4.3 liter Merc stalling after winter dormancy

The fuel pump should have power when the key is in the Start position, from the terminal on the starter...... <br />Yellow/red I Think, don't have a book right here....<br />Then it draws power from the Ignition circuit, thru an oil pressure switch,..... When the key is in the "Run position.......

 

[Don S]

Re: 4.3 liter Merc stalling after winter dormancy

It's probably the oil pressure switch. I see several every spring. To test, just jump the 2 wires on the switch (item 5 below)<br /><br />

 

[stanms]

Re: 4.3 liter Merc stalling after winter dormancy

It was the oil pressure switch... Thanks for the advice and the diagram... the part was $16... alot better then a shop visit !!!!!!!! THANKS!!!!!!!!!

 

[robfogle]

Re: 4.3 liter Merc stalling after winter dormancy

Dob S,<br />I just purchased a new to me Bryant 196 with a 4.3L alfa 1. There was some strange wiring and I've discovered that the previous owner wired the fuel pump up to the hour meter which is in the engine compartment. I have discovered, through you post that the oil pressure switch is missing. All that it there is the wiring. If I read the schmatic corectly this also powers the choke control circuit. I'm thinking this is why it is very slow to warmup and floods easily when cold.<br /><br />If I'm correct then the parts that I will need are:<br />87-864252A01 KIT-OIL SENSOR 1 $25.20 <br />22- 28624 1 FITTING-T 1 $5.45 <br /><br />The web page that I am getting these Part numbers from is: Mercury Parts Express <br />Can you let me know if I'm even close to the correct parts.<br /><br />Thanks<br />Rob

 

[stanms]

Re: 4.3 liter Merc stalling after winter dormancy

I cannot see a diagram at the website you posted so I do not know what exactly is included in the "Oil Sensor Kit" you are fixing to buy. The Oil Switch that goes in the fuel pump/choke circuit is mounted just above the oil filter on the back right sid eof the engine. It is connected to a Tee fitting that mounts onto the block. The Oil Pressure Sending Unit is mounted on th eother side of the Tee fitting (perpendicular to the Oil Pressure Switch... I hope that makes sense). I had to take both of them out to replace the Oil Pressure Switch ao I was going to buy a new Sending Unit while I was stuck back there in the engine compartment, but that part was $40 at my dealer so I opted to reinstall the old one. The new Oil Switch was a different design then the old one... less prone to corrosion according to the service tech at the dealer. I installed it and all my problems went away.<br /><br />I don;t know if this helps you at all. If you need a diagram of the whole circuit (more then the one posted previous in this train) let me know and send me an email address. I can scan it at work and email it to you. It i very helpful and will surely let you rewire yours back to stack. It sounds like your previous owner may have had the same problem and jury rigged it to work. You may be missing the low oil proteciton that this switch circuit offers. Not really a problem unless oyu ever run low on oil I guess. Well.. except for the choke. <br /><br />Oh yeah... My switch was only $16. That was the switch only (2 pieces... a switch and a short gasketed wiring harness). Yours may include the fitting or something like it... or just be more expensive then my local dealer (this is a genuine Mercruiser Part I am speaking of).<br /><br />Thanks... hope it helped!!!

 

[robfogle]

Re: 4.3 liter Merc stalling after winter dormancy

I'm going to pickup the parts today and get them put in. Hopefully it will solve the choke problems. <br /><br />Thanks for the info.<br />Rob