Boat motor help, wont start.

[Swampthing]

The guy we bought the boat from rigged a push button along with toggle switch after the factory key switch went bad. It worked for 3 years for us , until this spring when i was trying to get some navigation lights working. I was hooking everything back up to battery and noticed 2 loose wires. Checked his toggle switch and there were only 1wire into it. One was hot and out that to missing wire from toggle. I ran the other to battery ground. Now the motor turns over and electric choke works, just wont fire. Any ideas?

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[Hodag Hunter]

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Check for spark and fuel

Pull spark plug what does it look like?

Spray a little starting fluid in carb if you have spark.

[Dewey]

Did you run the carb out of gas before storing? Bad gas and especially ethanol blend can really screw up a carburetor. I neglected mine before storing last year and in spring it would not fire. Carb got all gummed up over the winter and needed to be tore down and cleaned.

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[Stanley]

Pull the spark plugs pour a little gas in the cylinders. If the engine pops off you have spark and are getting no gasoline. If the engine doesn't pop off you are getting no spark. If no spark check the plugs first. If you have no spark with different plugs, then you will need to go deeper into why no spark. If the engine pops off then pull a bowl on one of the carbs to see if there is gas in the bowl. You should be able to pump gasoline into the carbs with the bulb pump (it should take about 7 pumps and the bulb should get hard). If you have gasoline in the bowl the jets are more than likely gummed up. If there is no gasoline in the bowl the fuel pump is more than likely not getting gasoline to the carbs. This will get you to a point where you now know the fuel pump is the problem. Good luck.

[magicman54494]

if toggle and button, wouldn't the toggle supply power and the button be for starter? if so, why would you run toggle hot back to ground? wouldn,t you get a short? shouldnt the toggle have hot in and out?

[Swampthing]

if toggle and button, wouldn't the toggle supply power and the button be for starter? if so, why would you run toggle hot back to ground? wouldn,t you get a short? shouldnt the toggle have hot in and out?

Your right Magic, i mispoke the other wire was'nt a toggle hot back to ground it was just a ground from wire harness.

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[Swampthing]

Thanks for the tips guys 2 of the plugs were horrible, replaced them all and had spark. So i decided to put a little gas in cylinder and it popped off right away and died. That's when I took a break and checked my phone to see any responses to my post. Im thinking now that I wish i would have ran the carb dry. I checked all the fitting on the fuel line and 1 was loose, but that didn't fix it. I repumped the bulb and I was 1 pump away from hard and i could see a stream of gas shoot out the front of carb and then the bulb got soft. Im not exactly sure how to drop the bowl but there was a little drain plug at the bottom of bowl. I pulled the plug but nothing really came out. Im thinking now mabey fuel pump.

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[Swampthing]

By the way the motor is a Mercury 500 ( 50 horse). Year is 1976 i belive

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[Bowhunting Brian]

I wouldn't run the carb dry. it can dry rubber gaskets and fuel lines out and they crack. (even faster if you have ethanol in your gas) I always treat my gas sta-bil marine and once in a while I run seafoam through to clean everything out and I never have fuel problems.

[Stanley]

By the way the motor is a Mercury 500 ( 50 horse). Year is 1976 i belive

[ Post made via Android ]

4 cylinder 2 carbs? I owned a 1979 50 hp Merc years ago. I would pull the fuel line that goes to the carbs after the pump. Roll the engine over with the starter and see if the pump is moving fuel. If you pulled the plug on the bottom of the carbs and it was dry you are not getting fuel into the carbs. If the pump bulb didn't push fuel into the carbs the needle valves/floats may be stuck.

[Dewey]

I wouldn't run the carb dry. it can dry rubber gaskets and fuel lines out and they crack. (even faster if you have ethanol in your gas) I always treat my gas sta-bil marine and once in a while I run seafoam through to clean everything out and I never have fuel problems.

I have been told by marine mechanics that Seafoam is probably the worst thing to use. It does a great job cleaning but problem is it eats away at rubber seals and does much more damage than you could ever do running the carb dry.

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[Dewey]

I wouldn't run the carb dry. it can dry rubber gaskets and fuel lines out and they crack. (even faster if you have ethanol in your gas) I always treat my gas sta-bil marine and once in a while I run seafoam through to clean everything out and I never have fuel problems.

I have been told by marine mechanics that Seafoam is probably the worst thing to use. It does a great job cleaning but problem is it eats away at rubber seals and does much more damage than you could ever do running the carb dry.

I only run ethanol free gas to avoid any problems.


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[ Post made via iPhone ]

[Bowhunting Brian]

I wouldn't run the carb dry. it can dry rubber gaskets and fuel lines out and they crack. (even faster if you have ethanol in your gas) I always treat my gas sta-bil marine and once in a while I run seafoam through to clean everything out and I never have fuel problems.

I have been told by marine mechanics that Seafoam is probably the worst thing to use. It does a great job cleaning but problem is it eats away at rubber seals and does much more damage than you could ever do running the carb dry.

[ Post made via iPhone ]

I will relate that to archery shops. you can go to 10 different shops and get 10 different answers. I am not a scientist, but I can tell you I have never had an issue in all the years that I have used it.

[Dewey]

I wouldn't run the carb dry. it can dry rubber gaskets and fuel lines out and they crack. (even faster if you have ethanol in your gas) I always treat my gas sta-bil marine and once in a while I run seafoam through to clean everything out and I never have fuel problems.

I have been told by marine mechanics that Seafoam is probably the worst thing to use. It does a great job cleaning but problem is it eats away at rubber seals and does much more damage than you could ever do running the carb dry.

[ Post made via iPhone ]

I will relate that to archery shops. you can go to 10 different shops and get 10 different answers. I am not a scientist, but I can tell you I have never had an issue in all the years that I have used it.

I have run all of my motors dry before storage for 25+ years(boat, lawn mowers, weed eaters, pressure washer, ice auger, snowblowers, generator, chainsaw) and never had a single problem till last year with my boat motor because I left gas with ethanol blend and Seafoam in the carb. The guy that worked on mine is a certified Mercury technician and said he sees it all the time. He showed me the damaged stuff from my carb that was eaten away from Seafoam use over the years. Like I said the stuff does a great job cleaning fuel systems.........too good actually and that is where the damage is done. Not telling you what to do just passing on what I learned from a very reputable marine mechanic.

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[Swampthing]

By the way the motor is a Mercury 500 ( 50 horse). Year is 1976 i belive

[ Post made via Android ]

4 cylinder 2 carbs? I owned a 1979 50 hp Merc years ago. I would pull the fuel line that goes to the carbs after the pump. Roll the engine over with the starter and see if the pump is moving fuel. If you pulled the plug on the bottom of the carbs and it was dry you are not getting fuel into the carbs. If the pump bulb didn't push fuel into the carbs the needle valves/floats may be stuck.

Yes , Merc 4 cylinder 2 carb. Is there a standard carb and fuel pump rebuild kit that i should go with ? Or does a guy salvage what he can ? Are there certain items on the must replace list?

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