I don't think those motors have a thermostat.

What motor do you have? Need a serial #. O5herwise it could be a 3,4,6 cylinder motor. Is it carbed or injected

It is a 1986 model

Is it adjusted correctly? Does.the bracket have both bolts in it?

I like the small Chinese pumps. I buy like 10 of them at a time and rebuild them with BRP rebuild kits. A $100 pump for $30 it is the gaskets that are garbage the housings seem OK so far.

135
1988
exlpto
b241881 - c100860

What happens if you leave the choke on until it actually starts? I usually leave the choke on until the motor is physically running. Once it's running I will push the choke off when it starts to bog.

Left side of the video, the bracket screwed to the transom is what you need. That is a a seastar/teleflex bracket. The piece on the motor is the correct mounting location look for the Mercury bracket...

https://m.youtube.com/watch?v=AY10GEsCQ34 look in the catalog for this set up. The bracket may be in Mercs catalog.

Look through the teleflex/seastar catalog on this sight should have what you need.

Hard to believe it has low compression if it is pushing a 14' boat at 15 mph or idling for that matter. What is your starting procedure?

I personally would not fix it and not because it is a bad motor. Just because the later models had improvements to make them run better. Anything OMC after 1980 is a good choice.

I would change the water pump and thoroughly clean the carb and install a good quality kit.

Are you a troll? this was answered on another site.

Thank god for google, How else would you go off on a wild goose chase. Get new quality carb kits and rebuild your carbs. No matter ho much you adjust the float if the needle and seat are bad gonna...

You are not idling at 25 degrees can pretty much guarantee that. If it dies when shifting could be as simple as to low of an idle. What is your compression? Spark to all cylinders jumps a 7/16" air...

Have you checked the eye?

Yes you do need a battery connected. The rectifier uses the battery as a voltage regulator.

before anything do a compression test.

Metal box with the cover and all the wires going to it is your CDI, just an early version.