Fuel starved acting 1993 75hp Mercury Outboard 2 stoke, 3 cylinder

[pkb4]

The boat came to our boys after their father passed away. It sat roughly 3 years due to his inability to work on or use it. Their dad took very good care of the boat during the time he had it (wanted it to be safe for the boys). My wife and I pulled it home about a month ago for the boys and I've been working on it almost everyday since.

• carbs were shot due to sitting (changed with a purchased rebuilt set)
• water pump was shot (changed and now has water out of the tell tale)
• fuel filter changed
• new spark plugs
• new battery
• fuel lines were cracked and had to be replaced.

Now the motor will crank but acts fuel starved. It will crank but, it will not stay running. It almost appears to run better cold at times. It has to be primed before each start. I was afraid something had made its way to the new fuel filter so that was pulled and blown out with a compressor. Any help would be appreciated. Coming up on fathers day and would love for them to be able to take her out.

 

[jsmilliken]

have you checked to see if there is spark?

 

[pkb4]

Yes, there is a spark. It will crank and runs for a few minutes but, then it dies. It's acts like it's running out of gas.

 

[fmt2bx]

I just joined this forum 2 weeks ago, so not an expert. However I have spent a week troubleshooting my "new to me" outboard fuel starvation issue.
Turned out the quick fuel disconnect wasn't working right and allowing air/no fuel to go to the engine. You might want to check it. There are O rings in them and mine was missing one. Brand new part too!!!
I hope you find the issue.

Good luck.

 

[DavidMoore]

If it acts like it's running out of gas, then it's a good chance it is running out of gas. You just have to figure out why.

You replaced the carbs, new fuel lines, and fuel filter, what about the fuel pump?

If the fuel pump is OK then how about air leaks like fmt2bx had.
Install a clear plastic pipe between the fuel filter and carb, start the engine, if there are air bubbles there is a leak, work backwards through the fuel system and check everything thoroughly until the bubbles stop.

If there are no bubbles look for blockages.
Typically
- Fuel vent on tank is open, for built in tank check fuel vent line is not blocked.
- Primer bulb is installed with the arrow pointing directly upwards (I don't mean in the direction of flow, that's obvious). I mean also pointing upwards.
​- Fuel / water separator, if fitted, clean and full of fuel.

It might also be interesting to know

What is your starting procedure?
What happens if you squeeze the primer bulb just as the engine is about to die?
What happens if you give the engine a little squirt of choke just as the engine is about to die?
Once it dies, will it start up again straightaway after priming, or do you need to wait for the engine to cool?

I hope you solve it before fathers day, good luck.

 

[DavidMoore]

Also the fuel pickup inside the tank could have a mesh like strainer, that is another common place to find a blockage.