1977 70 hp evinrude runs grest for awhile until I get to my spot...and then.....

[VTbasshunter]

After leaving the boat launch my 70 hp evinrude outboard starts right and runs great pushing my 78 monarch mcfast. After running to my spot and fishing for alittle while, I try start it back up easily and get going. Once up to speed it starts to bog down. At full throttle it goes then bogs. Then bogs for a long time until I get frustrated and go to land. Any suggestions on this?

 

[racerone]

Test run with a known to be good hose and tank.

 

[Bosunsmate]

If you prime the bulb with engine off does it go hard? And stay hard?

 

[Tim Frank]

Test run with a known to be good hose and tank.

^^^^ +1

 

[82rude]

It could possibly be a coil breaking down.Runs ok till it heats up then breaks down.Stop fish,cools,runs ok till it heats up again.