69 rude problem

[chiefcatchemall]

Have a 69 evinrude sportwin 9.5 horse. Took it out and it ran great for 10 mins or so then when I took my father out later that evening it ran good for 5 mins then lost a lot of power. It was running more like a 5 horse. I cleaned the carb and changed the plugs right before I took it out so I know its not that..I have had this problem before. Sometimes itll run great then after a little time it bogs down. What could cause this? I have new fuel pump parts coming in the mail...

 

[tx1961whaler]

Re: 69 rude problem

Have a 69 evinrude sportwin 9.5 horse. Took it out and it ran great for 10 mins or so then when I took my father out later that evening it ran good for 5 mins then lost a lot of power. It was running more like a 5 horse.

If the spark quit on one of the cylinders, then it WAS a 5 horse.
I'd pop the flywheel and see if the coils are cracked. If they are, they'll fail when it heats up.

 

[Daviet]

Re: 69 rude problem

Start with the simple stuff first, compression and spark tests. If the spark checks ok, run it long enough to act up and then recheck spark. If you have a coil acting up it may have to heat up before it missfires. If all that checks out it is time to check the fuel delivery system.
Try pumping the primer bulb when it acts up, if that helps you will need to rebuild/replace your fuel pump.