Too much oil??

[sambluckie]

Recently purchased a used boat w/ a 1977 Evinrude 70 hp. Previous owners said it ran great the last time it was used and then after a lunch break, the motor would idle well but bog down under throttle.
While talking about it with them, they claimed to have mixed the oil and gas at a 40 to 1 ratio. My question, is that enough to foul the plugs and carb??
It cranks and idles well.

 

[racerone]

The 40:1 will not cause any problems.------First thing to do is a compression test. ----Post your numbers here.

 

[oldboat1]

Run 50:1, but issues you describe more likely to be dirty h.s. orifice in one or more carbs. I would get an adjustable spark tester and measure the spark on each lead (look for 1/2 inch), then disassemble carbs and soak al metal parts in solvent (I leave the jets in place, rather than risk damage, but remove plugs before soaking.) Get three kits and remove expansion plugs on tops before soaking. Do one carb at a time to avoid reassembly mistakes. Run soft wire through all orifices, and finish by blowing carb cleaner through using plastic nozzle. Be sure to clean all openings in each of the nozzles that run vertically in each carb.

Change out the impeller on any newly acquired motor.

 

[sambluckie]

It may be a few weeks, but I will get more information posted.

 

[sambluckie]

I was planning on purchasing a new fuel tank and fuel line to start out fresh. I saw on a motor exploded view that there is a fuel filter attached directly to the fuel pump. Could this be clogged and adding to the bogging down?

 

[oldboat1]

Could be. Clean it as regular maintenance.