40 HP Merc Gas Problem

[raedeus]

Hello to All. I'm new to the forums and hope you guys can help me out.

I have a 1970-something Mercury 402 40HP outboard motor. Last fall I started having problems starting the motor. Sometimes it would start and run fine and then it would just not start at all. So I began working on it a month ago. Here's what happened.

Day 1: Would not start what-so-ever.
Day 2: Would start and run immediately for 10 seconds and clunk out. Did this 3 times and then would not start at all.
Day 3: Will not start.

So, I have a new fuel tank, new fuel line, pump ball, and connectors on each end. Still, it will not start and the one thing to note: Spark plugs are dry!

Does this motor have a fuel pump and if so where? And, where is the fuel filter located so I can take it off and either clean it or replace it? Any help or suggestions would be highly appreciated. Thank you.

 

[JB]

Re: 40 HP Merc Gas Problem

Howdy, raedeus.

Welcome to iboats.

Go to the Engine FAQs for Outboard won't start.

Let us know what you find.

 

[raedeus]

Re: 40 HP Merc Gas Problem

Thanks JB! I'll start there.

 

[raedeus]

Re: 40 HP Merc Gas Problem

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[raedeus]

Re: 40 HP Merc Gas Problem

Well, for anyone interested in my problem here's what I did to fix it:

I replaced the gas line connector at the motor and all gas lines in the motor. I then rebuilt the fuel pump assembly (gaskets and diaphram) and did not have to replace the check valves since they seemed fine. I also talked to the boat dealership where I got the parts and they said that my motor (being a 1977-79) make was designed for running leaded fuel. That being said they recommend running low, or no if possible, ethanol fuel through the motor. So, I'm taking that advice and using Seafoam in every tank of gas.

Anyway, after all the replacements the motor still did not want to start. I even checked the spark plug wires with a tester to make sure that was working. I then ran the motor without plugs to force some of that old gas out of the motor. After doing this twice I started getting the motor to kick over and eventually it did. Once that old gas ran out it ran better than it ever has ran. What's great is the parts cost me less than $20. I'll be out on the lake tonight to see how it runs.

--raedeus