sonofarebelson
Recruit
- Joined
- May 12, 2007
- Messages
- 3
So I bought this motor back in July off craigslist to put on my 18ft alum starcraft. I mounted my self and took it out multiple times on the local lake to test it out and make sure everything was rock solid before I headed out to bigger water on the bay. All in all I probably put 20 hours on the motor and except for a clogged oil filter which an alarm alerted me to it ran great. 2 days ago I took it in the salt for 5 hours and it ran fine until I started to head back and it was only reaching maybe 10 kts at full throttle when normal full throttle is 23 kts on flat water. I backed off the throttle and started to limp towards the dock. Half way back I tried throttling back up and low and behold it the engine revved up like normal. Next day I took it to lake to see if I could duplicate problem and ran it for 10 minutes throttling up and down no noticeable issues. Then it does the sluggish thing where it wont rev up with increased throttle then it sounds like it is missing on a cylinder. I'm still close to the dock at this point so I head back in. It ends up dying on me 3 or 4 times in 300 yards back to the dock. I don't normally motor my boat on the trailer so I winch it on. Drive the 10 minutes to my house, put the muffs on, starts right up then dies. Try to start again, engine won't crank over, fly wheel is locked, upon further inspection, the block at the middle cylinder is split. This engine still had vro system in tact, I recently replaced all the old brittle oil injection vinyl lines and had been running 50:1 while I made sure oil injection was functioning. Basically oil injection was fine, I could see oil getting sucked into cylinders and the oil level in the tank was going down. Only issue was oil in the top cylinder oil line would slowly fill with oil while the other 2 oil lines had oil getting sucked immediately into cylinder. To combat this issue, I was running 100:1 gas mix to make sure top cylinder had lubrication while oil filled line and made it to cylinder. I had been running this way for 10 hours no issue. Any one have any idea why this motor blew up so quickly? Again, it had been running fine for 5 hours on the bay doing full throttle no issues, if it had been an oil injection issue I would think it would have blown up hours before or as soon as i hit full throttle. It should also be noted that this motor was in pristine condition for its age, cosmetically flawless and it had been obviously well taken care of. The motor had been sitting for a couple months on a stand as the previous owner damaged his boat. The guy I bought it from did say he would start it up every now and then. This is a huge shock to me to have such catastrophic damage. Anyone have any thoughts on what caused the middle piston to go? I was pretty vigilant on making sure oil was running through those lines so I tend to think the oil injection wasnt the problem and on top of that I had 100:1 mix running at time of failure.