8 hp Mercury 2001 will start but dies unless primed

[treefish]

2001 8 hp merc. SN: OT223656.
Checked stator: Wt/Gr - Gr/Wt = 400 ohms. (good is 350-450)
Checked trigger: Br/Wt - Br/Y = 748 ohms. (good is 850-1100, so is this bad?)

I have cleaned the carb and installed new gasket kit.
The motor will fire immediately, but will die if I die if I don't prim it about every 20 seconds.

Should I get a new trigger? or something else.

Background... I'm pretty sure this engine was overheated. When I started working on it the pee-hole tube was full of sand.
It pees good now. I cleaned it all out.

 

[treefish]

Re: 8 hp Mercury 2001 will start but dies unless primed

hello.........hello.....hello.......hello

 

[hotrod53]

Re: 8 hp Mercury 2001 will start but dies unless primed

Are you sure that you have the vent open in the fuel tank or it is not blocked? If so, I would suggest a fuel pump rebuild, in my case a carb kit did not include all of the fuel pump parts, it was a seperate kit. Also, the ethanol in the fuel is eating up our fuel lines, maybe a few dollars worth of new fuel line would be worthwhile to be sure.

 

[Wingedwheel]

Re: 8 hp Mercury 2001 will start but dies unless primed

As Hotrod53 says, a new fuel pump kit or when you prime it is your bulb soft? It may just be the bulb is bad and leaking down.

 

[JDusza]

Re: 8 hp Mercury 2001 will start but dies unless primed

Anyone care to back up a few steps?
The engine starts and does run. Thee is nothing wrong with the ignition system. No need to be thinking about stators and triggers.

Fuel is not getting through the carburetor to the intake manifold. When when fuel does get to the carburetor, the engine runs fine.

Could be anything from closed tank vent, leaking fuel line, leaking bulb, clogged low speed jets, bad fuel pump.... stuck needle valve. There 's a few more things to check before we throw money at it. Disconnect the fuel line from the fuel pump to the carb at the carb. Wrap the fuel line end with an old rag that will get gas soaked. Crank the engine and see if the pump moves fuel; should be squirting into the rag.
Does the engine run if choke is used instead of primer bulb?

Also, if you suspect the engine has overheated, you need to check the waterways, water pump and thermostat.

There's more going on here.... What's the history on this engine? Has it ever run for you?

J

 

[treefish]

Re: 8 hp Mercury 2001 will start but dies unless primed

Thanks for the replys, from all of you.

Ok. Yes, I have removed the lower unit and installed a new impeller. Water pumps great through the engine. I also removed the thermostat and cleaned that passageway. The thermostat operates as it's supposed to (doesn't allow water to flow fast until the engine heats up a little).
As far as fuel lines, I'm using the tank and fuel line from my 15hp to test it out. While hooked up to my 15hp everything operates perfectly.
What do you guys think about me swapping the carbs out from my 15 to my 8? Are they interchangeable?
I'm going outside to give it a shot. I'll report my findings.

Thanks again for the replies.

 

[treefish]

Re: 8 hp Mercury 2001 will start but dies unless primed

Before I changed the carbs out, I noticed that the bulb never got tight when I squeezed it. After taking the carb off and replacing it with my 15hp carb the bulb gets tight and the motor runs seemingly as it should.

So, what did I lose when putting the carb back together that would prevent the bulb from getting tight?

 

[treefish]

Re: 8 hp Mercury 2001 will start but dies unless primed

Turns out I hadn't lost anything. I tore my carb apart again and checked all the jets/passageways took the fuel pump apart and checked all the gaskets in there and the diaphragm. Everything looked good, but I did flip the float upside down. The motor runs just fine now. Could the float being upside down have caused the original problem?

 

[Wingedwheel]

Re: 8 hp Mercury 2001 will start but dies unless primed

Definitely

 

[treefish]

Re: 8 hp Mercury 2001 will start but dies unless primed

Thanks to all of you for the guidance. The motor runs great now.