1975 Mercury 8500

[tompowers85]

I have a merc 8500 that i got last year. I had trouble last summer so i spent the winter trying to fix the problem. I rebuilt both carbs I have ajusted the float levels and tested the compression, but i cannot get any power out of the motor. I went out today and for some reason when i prime the bulb the carbs are still leaking, they are pooring gas, and there is air getting in the lines. I have replaced all of the fuel lines. I am going to go over them all again. The bulb looses pessure after about 1-2 minutes. Will the air in the lines push more fuel pass the floats and cause the engine to flood and loose all the power? I only went 5-10 mph. I want to make sure that will cause that kind of decrease in power.

 

[rabidfish]

Re: 1975 Mercury 8500

You might give the fuel pump diaphram a thorough inspection...

 

[tompowers85]

Re: 1975 Mercury 8500

i have replaced everything in the fuel system fuel pump and all. I had heard those diaphrams will leak air.

 

[Laddies]

Re: 1975 Mercury 8500

If you have fuel running out of the carbs, then you have a problem, with needles and seats or floats

 

[Ben Konopacky]

Re: 1975 Mercury 8500

Carbs leaking fuel when primed= float adj.and /or<br />bad needle valves or seats. Air in Lines checl All<br />connections and"O" rings from tank to eng.

 

[tompowers85]

Re: 1975 Mercury 8500

The shop manual says to set the floats to 1/4" so i set them to 14/32" to try to stop the leak should i set them even lower? I have replaced the needles and seats twice in each carb.

 

[Ben Konopacky]

Re: 1975 Mercury 8500

check your floats ,could be hung up and not <br /> moving the needle valev closed.check it <br /> before its reassembled.Hows the seat gasket?

 

[joblo33]

Re: 1975 Mercury 8500

I thought it was normal for these motors to spill fuel when the bulb is primed firm. I have a few merc 500's and they all do this.