New to me 1993 Johnson FastStrike 150

[daculatruck50]

I have a 1993 Johnson FastStrike 150 Model #j150glera Serial #03457429

I just got the motor on a boat a recently purchased. The power head is 3 years old and has 2 hours on it from when it was first put on I have taken it out twice and taken it really easy (barely getting to 5k Rpm's for a short period of time). Is there anything i should check before going any further with the motor? The water pump works perfectly 25+psi at 5k. Anything i should look at or anything would be greatly appreciated. But onto my questions.

1. I want to add a temperature gauge to my motor. I have found a gauge i want that matches but i have no idea about wiring the gauge. I know i have to wire 12+ and ground but i assume the 3rd wire is a temperature sending unit but i dont know anything about that. Thats what im in the dark about. I really just want to know what it is i need to run a temperature gauge.

2. I know i need to run BRP XD35 or XT3 oil in the motor at 50:1 correct? Or do i need a little heavier oil because the engine is still in "break-in hours". My main question is do i need to run a seafoam additive or stabil ethanol additive? I know there is ethanol. Thank you in advance for the help.

[Bassmeister]

You need double oil while breaking in. Mix 50-1 in the tank along with what the vro does. BRP xd-30 is good to use during breakin, but I would use XD-50 after and decarb every 100 hours or a season. Most people will tell ya the temp gauges aren't very accurate. I'll defer to the gurus on the temp gauge.
Run a good fuel additive till it's broke in , then mabye some seafoam every other tank or so, but don't stop using a good fuel additive such as BRP 2+2.

[daculatruck50]

My VRO is not functioning. Three years ago when the new powerhead was installed it was disconnected and the oil is pre mixed. How long do i need to run double oil in the motor? Im 99% positive that the powerhead has about 4 hours on it but if it doesn't will double oil hurt it really bad?

What additive do you recommend during break-in?
You recommend BRP 2+2 after break-in in every tank?
What exactly is de-carbing?

[Bassmeister]

You need double oil, for a minimum of 10 hours. If you haven't been doing that I would do it for 10 more hours @ double oil.
Yes. with the ethanol in fuels I run an additive in every tank for the fuel, you can run some type of carbon cleaner in every other tank just to help keep the carbon down.
Decarb, is spraying engine tuner down the carb throats while running on the muffs, to break up carbon around the rings and on top of the pistons. 1 can of engine tuner, follow instructions on the can, let her sit overnight, take her to the lake the next morning, run the hound outter her,change plugs and enjoy another season of boating.