Johnson Seahorse 7.5 (J8RCNR) - Mild surging when warmed up

[mthydro]

New here, but will definitely be spending some time on here, as there are some great resources.
My 1982 Johnson Seahorse 7.5 (J8RCNR) is having some issues. When it's cold it is running great, but when warmed up there is a hesitation/mild surging/loss of power.
I was told to run without the hood as there may be an exhaust leak.

I recently completed the following:
- carb rebuild
- plugs
- lower unit oil
- new fuel line from tank to motor

I can't see anything else wrong. Good steady stream of water coming out.

Any tips would be great!
Thanks
Mike

 

[racerone]

Install a new impeller ----Inspect thermostat.------Test run with another tank too.

 

[racerone]

Install a new impeller ----Inspect thermostat.------Test run with another tank too.----Spray some oil into it when running.----Should make it easy to find an exhaust leak.

 

[Bosunsmate]

How hot does it get? Can you still put your hand on the head?
Try a spark test 7/16 gap when hot