74 larson with johnson 140 2 stroke issues

[New boater 34]

I just bought a 74 larson with a johnson 140 two stroke the guy I got it from was having starting issues with it that's why he sold it I took it out on the river today started up ok little temperamental but idled sluggish when I got out of the no wake zone I went to full throttle and it didn't plane out and was only going roughly 6 mph sounded like it was boggin down the entire on the water i had the warm up lever up some cause it would die if it was all the way down im thinking thst was part of the mistake to but im learning I'm new to owing a boat and need all the help I can take on getting this outboard running better then it is currently any advice or help will be appreciated im currently looking up parts like plugs and wires stater coil packs (the guy replaced three before I got it) maybe carb rebuilds or new carb was told might be the prop to need a different pitch prop please help

 

[racerone]

Year / model # of motor?-----The trouble shooting always starts with a compression test.----Post the actual values here.

 

[New boater 34]

The motor is a 78 140TL78C I'm going out of town tomorrow so won't be able to do a compression test till Monday I'm just trying to get ideas to check when I get back

 

[racerone]

Do not spend any $$$ on parts until you confirm condition of this crossflow engine.

 

[Faztbullet]

Probably due a rebuild because of high ring pistons

 

[racerone]

Easy to inspect by removing bypass covers.