it just plain died

[DSigmond]

For three or four years now, I've had a 2007, 22' Cruiser. Nicely laid out, more stuff than I could have justified, and it all works, sort of. The 2010 Yamaha 115 had 380 hours then and starts right up, smooth idle, maintenance on schedule, only non-ethanol with SeaFoam. Now, at 500 hours, it still starts right away, has a smooth idle and scoots out pretty well.

So, a month ago, the engine went into safe-mode RPMs, soon the oil light came on. Still idles okay, I checked the dip stick: Nothing in there! Empty! I put in 3 quarts I had aboard, light went off and I headed home. A mechanic came over, changed oil, starts and idles ok, no oil in the water. Cruised the harbor for awhile, no oil trail, working okay. Went out and got on plane for 30 minutes, working ok. Went back: 2 quarts oil gone. Mechanic said nothing he can do while in the water, go to a dealer.

Dealer said compressions are all over the place, none over 100lbs. Should be ~200. Two plugs had the tab burned off. The oil was into the cylinder, flashed, then out the exhaust. He said it can go real fast when it goes south. New engine time.

While i've had the boat, the rpm's have never gotten up to the manual's 6,000. It never got over 5,200 for me, with the 13x19 prop she came with.

So, did I lug her to death? Thoughts? New Yammies are hard to get.

[kaelc]

Sorry for your loss. These things happen.

I had a chev 4.3L engine lose compression since the distributor cap was cracked and moisture was making it miss, unburned fuel ended up in the cylinders and we lost compression as a result. Expensive road trip 8k?

I'd post a few wanted ads on Facebook boat groups, craigslist and call marine engine dealers looking for a Yamaha trade-in.

[thataway]

I had that same engine on an 18' Century (about half the weight of a C Dory 22), with a 17" pitch prop--would reach 36 mph and 6,000 RPM.

So yes you were overcropped. Most likely lugged, especially if you ran it much on a plane.

I would check into rebuilding the engine. If not too bad you can over bore, fit new pistons, and rings. Do a valve job, probably do bearings and seals, since you have it torn down. If really lucky maybe just a cyl hone and new rings?? That will probably cost half of a new engine (probably $3,000)-and no worry about finding a 115 in today's shortage of outboards. You have relatively low hours--those engines should go from 1500 to 3500 hours.

[davidJ]

If you brought the boat 3 or 4 years ago and it had 380 hours on it and now it has 500, then you have been putting only 30 or 40 hours on it per year, and it looks like the previous owner only put 30 or 40 hours on it per year for about 10 years. I think it died from lack of use. If you only drove your car 30 or 40 hours a year for 14 years, I would think it would have problems too. If moisture gets into the engine and your rings rust then you will have problems like you do.
If you have the right prop, you should be able to max it out at 6,000 rpms, but you should also be able to cruise easy at 5,200 just fine.

It's a tough call on whether to rebuild a 14 year old motor or go for a new one if you can find one. If you go for a new Yammie you may be able to reuse your controls, cables, and mounting brackets to save a few thousand dollars. and maybe they will give you something for your old motor, and at least you won't have to tune it up this year. and your boat will be worth a whole lot more if you should ever sell, and you will get a warranty with the new motor. If you go with a rebuild, will they have or be able to get all the parts. if so, I would think it may cost as much as $6,000, I had a 70 hp rebuilt 20 years ago and it cost me $3,000.. They will rebuild the motor, then replace the impeller, thermostat, probably all of your fuel lines inside the motor and to your fuel tanks and a whole bunch of other things to make sure the job is done right. good luck.

[Barry Rietz]

It is obvious from what you described that internal engine damage has occured. The mechanics report that "two" spark plugs have had their electrodes erroded is one clue that leads me to think the engine was experiencing bouts of excessive heat. This could occur by running the engine without water cooling due to a faulty water pump or stuck thermostat. It could also mean the engine was running too lean a gas/air mixture. Or, perhaps there are huge salt deposits in the water cooling system restricting water flow. Either way, the engine is "toast" but unless there has been severe damage like a connecting rod through the cylinder jacket, the engine is very repairable. I would get an estimate of cost for parts such as; valves and guides; pistons and connecting rods; and a full gasket and seal set. Any experienced auto shop that does engine rebuilds would have the ability to do a rebuild. It's just a question of locating an engine machine shop that would not be intimidated by the relatively simple procedures. The only issue I see is getting the power head off the engine and over to the rebuilder. BTW, during disassembly, the cause of the problem should be relatively easy to diagnose.

[T.R. Bauer]