300x Powerhead

**36Tango** · 11-05-2025, 02:27 PM

At the LOTO Shootout Poker Run, my starboard 300x on our Skater 28 decided to do its best impression of a bag of hammers at about 80mph. Shut it down immediately, found a ramp, towed it home to the shed to deal with it another day. Pulled off the cover and see no holes. Turned it over and it started for just a second and I shut it back down, so it still rotates. Anyway, I need to pull the powerhead this weekend. Are there any words of wisdom? Any “this makes it much easier” ideas? I have seen that it can be tough to separate and they make a tool for it, but of course I do not have one. Does anybody have a picture of one? Thanks a bunch in advance!

**capteliminator** · 11-06-2025, 06:45 AM

Its pretty much nut and bolts. Need the lift ring to thread into the crank. If its salty, then be patient and keep at it until it breaks free. Remove the lower skirt to expose the power head bolts, disconnect the throttle and shift linkages, fuel and oil lines and main electrical plug in.

**36Tango** · 11-06-2025, 07:02 AM

Besides one Miami to Key West poker run it has been in fresh water. I do have the lift ring along with a chain hoist. It does not sound too complicated, but thanks for your input. I will have the rebuilder reinstall it.

**mr fun** · 11-06-2025, 07:57 AM

Wow , what a great action photo ! one of the best benefits of attending those type events are access to helo shots for a few bucks , don't know if there was any screaming but you guys were definatly Flying ! get that motor fixed and get back in the game !

**36Tango** · 11-06-2025, 10:17 PM

Originally Posted by mr fun

Wow , what a great action photo ! one of the best benefits of attending those type events are access to helo shots for a few bucks , don't know if there was any screaming but you guys were definatly Flying ! get that motor fixed and get back in the game !

That pic is from a few years ago when my son and I did the Miami to Key West Poker Run. We had plenty of air time in the Atlantic!

**36Tango** · 11-07-2025, 06:57 PM

Pulled the powerhead today. The lower left spark plug had aluminum on it and the electrodes were tight (no gap). We looked inside the cylinder with the borescope and we can see a broken ring in there. I don’t know how close the ring is to the top of the piston, but it must have broke off, letting the ring loose. We will know more once I get it to the shop.

**mr fun** · 11-07-2025, 07:10 PM

what kind of Rs were you turning and how many hrs on the motor?

**36Tango** · 11-07-2025, 11:03 PM

Originally Posted by mr fun

what kind of Rs were you turning and how many hrs on the motor?

55-5700 about 430 hours

**mr fun** · 11-08-2025, 01:42 AM

not sure what the recommended intervals are for rebuild a " mercury racing " engine of that size and those seem like conservative rpm's so, unless they winged up alot catching air like your photo i'd be looking at building both and starting fresh , and pray ( which I have for you ) you did not harm that block. what ever you decide you will have no problem selling those motors should you decide to as they are quite popular ( especially of freshwater variety such as yours ) just want to give you some encouragement to keep after what brought you here to begin with

Fun Out

**36Tango** · 11-08-2025, 07:32 AM

80% of the time my son is driving and I am throttling. I am pretty conservative and by splitting duties it makes it easier when getting air. Once in awhile I may bump the chip, but not much. I will take it in to have inspected and go from there. If I need to do both, I am good with that. I do not get on the water much, but when I do I do not like to have any mechanical problems. I will let you know what I learn.