1978 mercruiser 120 engine trouble

[jfreitag1988]

Ok so i have a 1978 120 mercruiser inline 4 engine that I just had rebuilt, I started doing repairs on the boat itself and the engine hasnt been started in about 5 months. So Iwent out and tried to start it and nothing it turns over and acts like it wants to start but nothing. By the way it started the last time with no problems at all. I tried adjusting the carb and the fuel is ok, and it is getting fuel also. Checked the distributor and wires all ok. It sound like its not getting enough fuel but i even tried starter fluid, and putting gas in the carb and still nothing. any ideas plz help.

[Erie Skipper]

sounds like a condenser to me

[Mechdave]

You need 3 things for the engine to start.

#1 It has to crank over at a decent speed. This should make cylinder compression above 100 psi. You can check this with a simple compression gage from an auto parts store or Harbor Freight.

#2 You need fuel to make it into the cylinder in the right amount. When you primed it it may have soaked the spark plugs which basicly shorts them to ground. Pull a couple plugs and make sure they are not drenched. If they are pull all the plugs and spin the engine over. This will blow the excess fuel out of the cylinders. Let the plugs air dry or blow them off with compressed air if you have it.

#3 You need spark. Pull the coil wire out of the distributor cap and hold it a 1/4 inch away from the engine block ( MAKE SURE THERE ARE NO FUEL VAPORS PRESENT FIRST ) have someone crank the engine it should jump a bright spark. If this happens plug the coil wire back in and remove one of the spark plug wires and repeat. If you have spark here also the distributor may be timed 180 degrees out. Do these steps and let me know what you find. I will try to guide you further when i get more info. Good Luck. Lets get that boat in the water before summers over.