Mercruiser 140 won't start

[Icehockeymaniac]

Someone has been tampering with my boat. I am sure that they switched plug leads around at first now I don't know which sequence they go back on in. I know the firing order 1,3,4,2 but I don't know which post on the distributor cap is 1. I can't seem to turn the enginge over by hand to check TDC on 1. I also think that my fuel tank has been topped up with water as the gauge shows more fuel than I remember. How do I check the fuel. It is a Mercruiser 140 4 cylinder about 1975. Any help would be appreciated

 

[Capt.Skid]

Re: Mercruiser 140 won't start

Pull all your plugs out and fit a socket on the crankshaft pulley nut with a 1/2 in. rachet if its not locked up the crank should turn rather easy. If it doesnt add some mystery oil directly in the cylinders through the spark plug hole and forget about for a day or so, then try to turn the engine again. If it dont budge shes locked up and you will need a shop manual to guide you through the tearing down of the top end. About your gas, you need to drain some out of the tank through the line that supplies your fuel pump. Water is heavier than gas and will settle in the bottom of the tank and come out first. If you got alot of water I would advise you to empty the fuel tank completely and start with fresh clean gas. How long has your boat be sitting?<br />Capt.Skid

 

[jamesr1]

Re: Mercruiser 140 won't start

I had the same problem with a boat that I purchased recently. I bought the boat without running it. ( got it pretty cheap ). Looking at the motor, the #1 cylinder is the front and it counts back. The distributor may have a #1 marked at the #1 post. From there you count clockwise around the distributor cap. Some mariene motors have a reverse rotation, in which case you would count counter-clockwise. If this is a 3.0 GM motor I believe it will count clockwise as did mine. You can tell by removing the dist. cap and watching the rotation of the rotor button.<br />To check for water in your tank you can pull a pint or so of gas (( from the bottom )) of the tank. Put it in a clear glass and wait about 10 minutes. If it has water in it, you will see it. If the gas is old, you may need to drain it completly.

 

[Icehockeymaniac]

Re: Mercruiser 140 won't start

thanks for the help, I have drained some fuel and it looks O.K. I just have to start the thing in the morning.

 

[Don S]

Re: Mercruiser 140 won't start

If you are just having problems turning the engine because of lack of access to the pulley, tighten the alternator belt and with the plugs out turn the alternator.<br />Hold your thumb over #1 cylinder sparkplug hole, and turn the engine over by hand. When you feel compression building you are coming up on #1 cylinder compression stroke. Continue turning till the timing mark lines up. That is #1 TDC.<br />Then look at you distributor, the rotor is pointing to #1 (or very close to it.) Hook #1 to it and continue with the rest of the firing order in the proper direction.<br />Disconnect the fuel line between the tank and the fuel pump before trying to start it. Hook fuel to a remote (outboard) tank with new gas.<br />Did you check your oil?<br /><br />

 

[Mahoney]

Re: Mercruiser 140 won't start

On the gas issue, I would not count on draining gas out of the feed tube to test it if your boat has been sitting on a trailer for any length of time. Depending on the amount of water in your tank, its true it will sink, however don't count on your feed tube to be low enough to draw that water.<br /><br />I tested gas drawn like that and it tested and looked fine,engine even ran without issue. I only found out later after trailering it to the lake and shaking up the tank, there was a ton of crud and water in the gas and the engine would not start.<br /><br />People on the forums will tell you if the boat has been sitting without running for a year or more, just plan on cleaning the tank and the fuel system. I was skeptical since my engine was running on the hose in the driveway, but I am a believer now for sure.

 

[jamesr1]

Re: Mercruiser 140 won't start

DO NOT START WITHOUT MUFFS!