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1979 70HP Evinrude bogs down at full throttle

K

kssnooz

New member
Hello Friends,
Have a 1979 70HP Evinrude model 70973R.
The engine runs fine at idle and slower speeds but if I push it to higher speeds/full throttle it bogs down and then revs back up/down/up/down. Once it starts this if I back off the throttle it won't go back to full RPMs until it rests a minute or two in neutral or off. It did this last season but we didn't get it out till late so I didn't worry about it too much. Will throttle up and run full speed for 30ish seconds every time then the issue starts.

Rebuilt carbs this spring, new plugs, new fuel lines from tank and in engine. New fuel pump. New impeller.

Throttle linkage is at 4 31/32" as per manual.

Here is a video.

20230506_143732.mp4

drive.google.com drive.google.com

Please help. It's driving me crazy.
Thanks,
Brian
 
Several things to try.----Run with another tank and hose.------Did you remove high speed jets to make sure they are clean ? ---Found in the bottom of float bowl.----It is starving for gas.
 
racerone said:
Several things to try.----Run with another tank and hose.------Did you remove high speed jets to make sure they are clean ? ---Found in the bottom of float bowl.----It is starving for gas.
Click to expand...
Fully rebuilt all 3 carbs just a month ago and ran welding brush up all the openings plus soaked them in parts cleaner for 3 plus hours before using the carb kit to replace all gaskets, rings, float and needle etc.

I am using a built in fuel tank, haven't tried another way yet. The lines from tank to engine and all fuel lines in engine and fuel pump are new.

I'll try a new tank and see. Thanks.
 
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