1972 20 Hp Merc Question?

[Big Fish Hunter247]

I have a 72 Merc 20 hp that I have rebuilt but I have ran into a road block I have compression which is about 90 on both cylinders I have spark and I have fuel but yet its wont fire and run??? could it be that the spark I have is not strong enough?

Any other options on what it could be?

By the way I have went through the Outboard Mechanic Program and Hennepin Tech so I have some idea of what might be going on but this has just got me baffled

Big Fish Hunter247

[boatfixer]

Be sure that your points are set @ .020. (Remember these are "maker" points). and your primary pick up timing is 1 to 7 BTDC

[Big Fish Hunter247]

thanks for the info I will give that a shot I hope this works

[Big Fish Hunter247]

here is an update on what I have goin on I have the points set where they should be but im not sure what the 1 to 7 that you were refering to? now that I have the points set where they should be I pulled the plugs and they are dry?? it wont even fire now if you squirt fuel directly into the cylinder? this is a motor that didnt run when I bought it so I'm not sure what the history of the motor is

Big Fish Hunter247

[marine_man]

1 to 7 degrees BTDC (before top dead center)

marine_man

[Big Fish Hunter247]

I took the carb apart cleaned it out but I am getting fuel up to the carb but its all comming out the front of it?

Can anybody tell me what I am doing wrong I really dont wanna take this into a shop it gotta be something minor?

Big Fish Hunter247

[Valv]

You probably lost the valve needle or it came loose when you closed bowl, re-open carb and check needle valve

[boatfixer]

Be sure the 2 arms at the needle valve are assembled correctly, and the float bowl vent is clear. if you are going to take it apart again, you should use a new needle and float, if you haven't already. You should always rebuild carb and install a new water pump on an engine rebuild. what caused the engine failure in the first place?

[Surface Tension]

When you squeeze the primer bulb up it sends gas to the carb. The inlet needle & seat stops the gas flow once the fuel level in float bowl gets to its correct height which is determined by the float. If you can continue to pump gas or it leaks out the throat, either your inlet needle & seat is bad or your float level is off. I'd replace the inlet needle & seat and check the float drop.

[Big Fish Hunter247]

I bought the motor for a rebuild project I needed something for a project for school but anyways all I have done with the carb is just clean it thats most likely my mistake there. but anyways thanks for the info guys I will give that a shot this weekend.

Big Fish Hunter247