# less than 20 hrs on rebuilt yam50 2 stroke....motor feels seized



## BonfireNSB (Sep 10, 2016)

I have a 50 hp 2003 Yamaha 2 stroke on my Dolphin renegade that was recently re bored and new pistons put on. Motor ran great through break in without issue until it bogged down (wouldn't go above 3500rpm) and i took it back to the mechanic. He gave it back to me two weeks ago "tuned up" and i put maybe 8 hrs on it since, and running wot for less than 1hr total intermittently. Motor was pissing just fine and had no weird vibration or noise. Yesterday it shook to a stop while running and wouldn't restart. Of course i had my wife and her friend on the boat 30 min before dark and had to get towed out of the lagoon (murphys law). Long story short... starter and all connections bench tested, scrubbed terminals at battery and all good. Then i pulled the plugs and put a socket on the flywheel and it is binding during rotation like the rings are sticking in one of the cylinders. 

Am i crazy or should a top end rebuild last longer than 20 hours?
I feel like the mechanic who shall remain nameless should get a verbal lashing from me?
I cannot in good conscience sell this motor to anybody but i cant deal with this crap anymore....what do i do????


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## Vertigo (Jun 3, 2012)

You could try to get help from the mechanic. Be polite but firm. That failing, sell the motor for parts and write it off as a lesson learned.


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## jonrconner (May 20, 2015)

Assuming there was oil in the tank one has to think your guy did something wrong. When you tell him what happened he WILL KNOW he messed up, it's just whether he'll decide to do the right thing or if you have to apply pressure.
JC


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## BonfireNSB (Sep 10, 2016)

jonrconner said:


> Assuming there was oil in the tank one has to think your guy did something wrong. When you tell him what happened he WILL KNOW he messed up, it's just whether he'll decide to do the right thing or if you have to apply pressure.
> JC


Thanks fellas i will talk to him monday and see what he says.


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## RunningOnEmpty (Jun 20, 2015)

Did the crank shaft get rebuilt as well?


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## BonfireNSB (Sep 10, 2016)

RunningOnEmpty said:


> Did the crank shaft get rebuilt as well?


I dont know?? is that commonplace for a top end rebuild for a cylinder wall issue like i had? I will ask him today.


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## No Bait / Lures Only (Apr 10, 2011)

BonfireNSB said:


> I have a 50 hp 2003 Yamaha 2 stroke on my Dolphin renegade that was recently re bored and new pistons put on. Motor ran great through break in without issue until it bogged down (wouldn't go above 3500rpm) and i took it back to the mechanic. He gave it back to me two weeks ago "tuned up" and i put maybe 8 hrs on it since, and running wot for less than 1hr total intermittently. Motor was pissing just fine and had no weird vibration or noise. Yesterday it shook to a stop while running and wouldn't restart. Of course i had my wife and her friend on the boat 30 min before dark and had to get towed out of the lagoon (murphys law). Long story short... starter and all connections bench tested, scrubbed terminals at battery and all good. Then i pulled the plugs and put a socket on the flywheel and it is binding during rotation like the rings are sticking in one of the cylinders.
> 
> Am i crazy or should a top end rebuild last longer than 20 hours?
> I feel like the mechanic who shall remain nameless should get a verbal lashing from me?
> I cannot in good conscience sell this motor to anybody but i cant deal with this crap anymore....what do i do????


My 90 Yamaha 1987 was rebuilt and modified 1990, after about 20 hours the motor blew a head gasket and ingested a reed screw into the intake reeds. My local mechanic located the issues, I contacted the engine builder and he eventually agreed to provide the parts with the return of the defected parts. Reassemble of the engine with new parts and it has been perfect since. Engine is still in service 2016. You should let your mechanic check his work for the issues you incurred...


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## RunningOnEmpty (Jun 20, 2015)

BonfireNSB said:


> I dont know?? is that commonplace for a top end rebuild for a cylinder wall issue like i had? I will ask him today.


The crank bearings get all the oil before the cylinders. If your motor failed from a lack of lubrication the crank might have been damaged. Yamaha uses a pressed crank assembly for your motor and they are not cheap. http://www.boats.net/parts/detail/yamaha/Y-6H4-11400-14-00.html


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## swaddict (Dec 19, 2009)

who did the work, there's only a few in the area?


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## BonfireNSB (Sep 10, 2016)

swaddict said:


> who did the work, there's only a few in the area?


I would rather not say because he does good work and after talking to him he has offered to figure it out for me.


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## No Bait / Lures Only (Apr 10, 2011)

BonfireNSB said:


> I would rather not say because he does good work and after talking to him he has offered to figure it out for me.


How did the engine issue and the mechanic rebuild work out for you? Please advise...


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## BonfireNSB (Sep 10, 2016)

stephenchurch said:


> How did the engine issue and the mechanic rebuild work out for you? Please advise...


Well he has the boat now and is fixing the lower end. Seems the old yamaha needed a complete makeover. He honored his word and is taking a long look at it to make sure it didnt have anything to do with his top end rebuild.


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## No Bait / Lures Only (Apr 10, 2011)

BonfireNSB said:


> Well he has the boat now and is fixing the lower end. Seems the old yamaha needed a complete makeover. He honored his word and is taking a long look at it to make sure it didnt have anything to do with his top end rebuild.


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## No Bait / Lures Only (Apr 10, 2011)

Sound like my mechanic, a 50 year mechanic, slow but great work. My 25 is a Frankenstein, parts from at least 3 engines, modified to near max. but still reliable. 3 lower units, prop shaft, recoil starter, throttle handle, new pistons, reeds, hydrotec engine parts : head, carbs modded, tuner exhaust, block ported. Since rebuild I have 250 hours on the Spear Glade X.


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## predacious (Sep 1, 2016)

jonrconner said:


> Assuming there was oil in the tank one has to think your guy did something wrong. When you tell him what happened he WILL KNOW he messed up, it's just whether he'll decide to do the right thing or if you have to apply pressure.
> JC



why would you believe the mechanic did something wrong ?

what if the oil tank was empty - empty because the owner failed to check it and the alarm was inop ? would that be someone else' fault ?

people are very quick to blame the people who work on everything...wonder why that is ??


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