Need some info on a boat motor please!?

Question

My father and I have been working on his boat that hasn't seen any action for 4 years. We got the bad boy out, changed the oil, drained out the old gasoline, changed the spark plugs, put new points and a router and cap on it. We've still been having some problems with getting it started. It will start, but we can't keep it running in idle. If we rev the motor and hold it in gear, it stays running, but we just can't get it to idle.

My girlfriend's grandfather said that the fuel line could be clogged up, or gunked up and it may need to be cleaned. However, I have no idea which one is the fuel line, and how to take it off, clean it and replace it.

Please let me know if you have any idea on what the problem could be, and if you think it could be the fuel line, please inform me on where to find it and how to take it off.

Again, it is a Mercruiser 3 liter alpha 1 engine, 90 hp. We think it could be similar to an 89 or 90 pontiac car engine.

Thanks!

Answer 1

Its a tough one - Its seems like that it might be on of those trial and error things.

Have a look through this site and see if you can identify the same model or design of the fuel pump etc !

It could also be that you need to give the carb a good clean!

Once thing is for sure is that it has to do with the fuel - You should also try and think about the idle speed it might need to be adjustment - You should be able to adjust this though the carb just! Its either starving itself of Fuel or its Flooding so adjust the intake of the fuel !

http://www.sterndrive.info/sterndrivepar...

Answer 2

I have had similar clogging problems with demolition derby cars. Dirt gets loose and finds its way into any filter or screen particularly now that this ethanol fuel is used. There is a cone shapped screen on the inlet fuel port of many carborators that may be clogged. Remove the fuel line at the point it screws into the carborator and you should find the screen. While the line is off you may as well blow compressed air in that line back to the tank (with the gas cap off) to clear any other possible obstruction.

Answer 3

carbs are dirty check the bowls

Answer 4

find the fuel tank.

find a tube or hose coming out of the tank and headed towards the engine.  That's the fuel line.

where it comes out the tank, is a fitting that has inside it an "anti-siphon" valve.  those get clogged and sometimes just go bad.  

you can test-run the motor without it, but to leave it out is just asking for an explosion.  I'm not kidding.

also, the carb(s) will need rebuilding.

but before going any further, I highly recommend a compression test and spark test.  not a *spark plug* test.  use an inline tester to verify that the electrical pulse from the coil(s) is adequate.