typically the starter solenoid is mounted on a bracket at the rear of the head

depending on engine it can be mounted in frt, over fuel seperator, or in the rear to the sideof distributor area.

You can also follow the yellow/red from Starter terminal 'S' (smaller terminal just to the right(block side) of the big + terminal.

Wiring is good Key to signal power out of solinoid

explain what its doing again, do you think you're losing voltage to the ignition when you stop cranking it ??

it cranks and wont fire. When you let go of the key -returns to the on/run position. It will stumble a few times as if it where running

Have fuel have spark have air. Was running on dyno not long ago. Nothing on the motor it self has changed. Only new things are fuel system. Cannon plugged into the rest of the boat Ecu is mounted to the boat. And running off boat batteries Confirmed charge is good and had a booster on it well cranking

That is what usually causes 'starting to fire' when releasing the key from 'crank.'

where do I test to see this. ? This would be the yellow/red wire I'm guessing?

I have a starter solinoid relay on order just to be sure. It's a P IA to get at so I think I should replace it to be 100%

No one? Everyone out enjoying the water

If the motor cranks over the yellow/red wire is fine.

Are you seeing cranking RPMs on the labtop?

Also what is battery voltage on the labtop while you are cranking?

sees rpm Lowest voltage saw was about 10. Had the batteries on a charger and tried using both. Made no difference