2006 Yamaha 50 HP 2 stroke reliability

harvey5560

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Sep 15, 2010
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Hello,
Im new here so please bare with me.

I am looking at buying my first boat to use for fishing. The boat I am looking at is a 2007 Sylvan 1600 Explorer with a 2005 Yamaha 40 HP 2 stroke motor which reportadly has less than 100 hours and is in great condition.

My question is, Are these a reliable motor? and are there any known problems with them?

The dealer selling it says it just started stalling when the throttle is opened up but promisies it will be fixed before he sells it.
 

robert graham

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Re: 2005 Yamaha 40 HP 2 stroke reliability

Re: 2005 Yamaha 40 HP 2 stroke reliability

Make sure it's fixed and running fine by doing a test run on the water, BEFORE you buy it. Sounds like carbs may need cleaning. Otherwise, probably as good and dependable motor as you could get. Buy a Yamaha Manual for that motor and study up on it's various parts, systems, preventive maintenance, etc., make sure it has a fuel/water separator installed, the dealer can put one on for you if it's not already on it. Take good care of it and it's just about bulletproof! Good Luck!
 

harvey5560

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Re: 2006 Yamaha 50 HP 2 stroke reliability

Thanks Robert for the reply.
Dealer just had all the carbs cleaned but he said he is going to have the mechanic go over it again as its not running 100 percent and he wont sell it until he does.
I have also told the dealer that I will not buy it until I water test it and satistfied that it is running properly.
 

harvey5560

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Re: 2005 Yamaha 40 HP 2 stroke reliability

Re: 2005 Yamaha 40 HP 2 stroke reliability

I heard back from the dealer today and he says the engine is running great. The mechanic cleaned the carbs again and adjusted the rich/lean screw to manufacturers specs.

The dealer water tested the boat and sent me a video of the motor running. From the video the motor started right up, sounded great, idled at 800 RPM and had a top speed of 35 MPH, which is what I expected.

My only question to the Yamaha experts is regarding the RPM. When the boat was at 35 MPH and WOT the RPM gauge appears to be reading only 3000 RPM. Is that normal?

I am scheduling a water test personally for Saturday and would like to know if there is anything else I should be looking at.

thanks
 

mphelle8vld

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Re: 2005 Yamaha 40 HP 2 stroke reliability

Re: 2005 Yamaha 40 HP 2 stroke reliability

I have two of these motors that have been converted to outboard jets, back when one was still turning a 10x15 prop, it would push my 1648 riveted semi-vee to around 38mph but it was turning an RPM of 5200. There's no way that motor will push any 16ft boat to 35mph at 3000rpm. Since the year of the boat and motor are different, the installed tach might not be the correct one (or set incorrectly) for the Yamaha 40. (also it might not be the original motor)

I would borrow a GPS w/mph on it and take it with you on your water test, if it indeed runs strong up to 35mph, the motor should be fairly healthy.

Post the video or send me a PM with a link.
 

rodbolt

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Re: 2005 Yamaha 40 HP 2 stroke reliability

Re: 2005 Yamaha 40 HP 2 stroke reliability

speed is irrevalent.
make sure the tach is tested against a known inductive shop tach.
that motor needs to turn at least 5800 with the load THAT day and ANY day.
its actually a Mercury engine with yamaha silver blue paint.
they work well but had the same electrical issues all mercs had that used Motoralar ign systems.
but for the most part, trouble free other than the standard all makes fuel system nasties.
 

harvey5560

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Re: 2006 Yamaha 50 HP 2 stroke reliability

Apparently I have fat fingers and cant type.

Anyways, mphelle8vld I know the thread was titled 2005, 40 HP... i've corrected it. Its actually a 2006 50 HP Yahama 2 stroke.

The motor is the same that came with the boat new ( at least year, model and HP), the dealer showed me the original sales invoice.

I'll try and see wether or not I can send a video in a PM. I cant in a forum post.

thanks

Harvey
 

rodbolt

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Re: 2006 Yamaha 50 HP 2 stroke reliability

the 06 50 2 stroke, well maintained, is about bullet proof.
its not uncommon when boats are being sold that they sit long enough that the fuel system fails.
seatrial it.
if it cannot turn close to 5500 RPM and cannot cruise at least 20 min at 4800-5000 RPM have it fixed or pass.
 

harvey5560

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Re: 2006 Yamaha 50 HP 2 stroke reliability

I have attached two screen captures from the video of the Tach and the Speedo. Maybe there is a way to calibrate the Tach??
 

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harvey5560

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Re: 2006 Yamaha 50 HP 2 stroke reliability

I've emailed the dealer and he is going to check the pole settings for the tach. from the video that he sent me the tach is made by Faria and according to their manual on their website the pole setting should be set for 6 for the 2006 Yamaha 50 HP 2 stroke ( sound right Rodbolt???)

The manual also indicates that the 2006 Yamaha 50 HP four stroke would require the tach to be set for 12 poles.. The dealer is going to check to see if by chance the original selling dealership mistakingly set the tach up for a four stroke instead of two stroke which would cause to tach to read lower than actual RPM's due to wrong pole settings.


Harvey
 

mphelle8vld

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Re: 2006 Yamaha 50 HP 2 stroke reliability

Speed is never irrelevant.

Had you posted a speed of 20mph, even rodbolt would have approached your problem as a sick motor. Given the boat was getting 35mph, he, as did I, decided to start with the tach. Until the storm passes, send me a PM with your email, I'd be glad to share my experiences with this great little motor. Mike
 

rodbolt

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Re: 2006 Yamaha 50 HP 2 stroke reliability

faria is italian for junk.
either have the dealer rig it with factory yamaha digital or walk away,

the guage package is the cheaspest SHEETIST ever.
also most likly why it doesnt work now.
 

harvey5560

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Re: 2006 Yamaha 50 HP 2 stroke reliability

Im really leaning towards a faulty Tach here... based not only on Rodbolts comments regarding Faria quality but also the sound of the outboard at WOT and the top speed the 16 foot aluminum SC Sylvan was able to achieve ( 35 MPH).

I found a webpage that tested a number of 2 and 4 stroke 50 HP outboards on a 16 foot aluminum SC boat and the results are listed below for the Yamaha 2 stroke. If the outboard was only getting to 3000 RPM then I should expect a top speed of around 10 MPH which is a far cry from the 35 MPH which was observed. The I found this information on is


http://www.trailerboats.com/output.cfm?id=2259109

YAMAHA 50 TWO-STROKE
Engine Speed Fuel Range1
(rpm) (mph) (gph) (mpg) (miles)
1000 4.1 0.6 6.8 122
1500 5.1 0.9 5.7 102
2000 6.4 1.3 4.9 88
2500 7.2 1.8 4.0 72
3000 10.5 2.2 4.8 86
3500 19.0 2.4 7.9 142
40002 22.8 2.8 8.1 145
4500 26.5 4.1 6.5 117
5000 29.7 4.9 6.1 109
54003 33.6 5.7 5.9 106
53004 31.6 5.6 5.6 100
Avg. 32.6
 

harvey5560

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Re: 2006 Yamaha 50 HP 2 stroke reliability

Thanks 99YAM40,

I checked that webpage and looked at the performance ratings for the 2002 Yamaha 50 HP 2 stroke with a Sylvan Excursion 1600 SC. THis is similar to my setup ( Sylvan explorer 1600 with 2006 50 HP yamaha).

The performance results again show that at 3000 RPM I should expect speeds in around the 8 -10 MPH range and at 30 MPH plus in the 5500 RPM range.

I appreciate the document. I'm really thinking tach problem and I am going to make sure the dealer looks into it before I water test as well I am going to bring a GPS to confirm speed.
 

rodbolt

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Re: 2006 Yamaha 50 HP 2 stroke reliability

why not just have the dealer rig it correctly with a 6y5 digital tach?
dealer cost is only about 240 and you may split it with them.
then you have trim, hours, trip hours, oil alarm visual and overtemp visual and low tank level indicates.
and it works for years and years, years longer if you cover the display when not in use.
 
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