blown powerhead?
 

1990 johnson 175 is the motor, with vro.

Running back in last night she shut down on us. I wasnt driving, sounded like we were at about 3/4 throttle. No vro alarms went off, just shut down out of no where.

Motor would not restart in neutral. If you took it out of gear and gave it 1/4 to half throttle it would fire up but as soon as you would back off the throttle she would stall.

I havent gotten down to run a compression test yet but im guessing we blew some pistons. Does this sound like a good guess?

Besides a compression test is there anything else we should look at?

If it is the pistons there will most likely be a 20 fisherman with a parts motor and trailer for sale dirt cheap in ohio***128557;:sad:

Do a compression test first . . . and DO NOT start or run the motor until you do.

could be something as simple as a bad fuel pump.

Compression results

5 cylinders at 90
1 at 60

Time for a new one

i would at least pull the heads off and look before i pulled the plug on that motor.

Theres an outboard guy around here that ive heard is very good and very reasonable on price.

Ill be giving him a call monday, atleast see what he has to say

Probably went lean and burned a piston. Crap gas and hot weather pre-detonation city.

i don't know how long you've owned the boat or what pm you've done, but before you spend much time or money on the powerhead, i'd make sure you can remove the lower unit. might not be a problem up north, but in the salty gulf, that vintage omc's had a tendancy to freeze on the drive shafts.

Sorry for that 60psi cylinder, doesn't sound good. I think you're in my neighborhood, I'm in Carlisle Twp. Who's the outboard guy?

Havent gotten it there yet but Brian at aquamarine in lorain

I've seen engines ALOT worse than that run for years. It isn't ideal, but unless that low cylinder has a stuck ring it should still run(just be slightly down on power from the weak cylinder).

I fired it up, it ran didnt want to start in neutral but would start with a little throttle and would idle back down... it sounded like there was a little bit of rattling going on and i shut her down right away.

anyone have any insight on that?

Rattling is a bad sound to hear in a 2 stroke engine. If it's piston slap, it's to be expected in an engine with slightly lower compression on one cylinder, but it could be worse.