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Altitude Adjustment Question

shueman

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I'm running an older 90hp Yamaha carb'd 2-stroke. We're headed to the Sierras next month for a few days and the lake is at 5500'.

I've been up around 4000' with no issues. Can't find my service manual so I thought I ask the o/b guru's on RDP.:thumbsup

Anything I can adjust to add air to the mixture (if needed)...?
 

SloWhacker

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I ran my carbed 200 Blk Max at Huntington (7000 ft) with no adjustments for yrs.Ran awesome.I just propped down when skiing.You will be fine.Should any issues arise,see Sheldon@ Sierrra Marina.Excellent mechanic.Youre gonna have a great time.I cant remember when Shaver was this full.:)
 

rivermobster

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I ran my carbed 200 Blk Max at Huntington (7000 ft) with no adjustments for yrs.Ran awesome.I just propped down when skiing.You will be fine.Should any issues arise,see Sheldon@ Sierrra Marina.Excellent mechanic.Youre gonna have a great time.I cant remember when Shaver was this full.:)
Any pics?? I've never been there, but the pics I've seen have been awesome.
 

shueman

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I ran my carbed 200 Blk Max at Huntington (7000 ft) with no adjustments for yrs.Ran awesome.I just propped down when skiing.You will be fine.Should any issues arise,see Sheldon@ Sierrra Marina.Excellent mechanic.Youre gonna have a great time.I cant remember when Shaver was this full.:)
Thanks...:thumbsup Despite it's age, the motor is like new inside...perfect for puttin' around looking for fish...;) Leaving this coming Sunday...
 

Luv2gofast

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I ran my carbed 200 Blk Max at Huntington (7000 ft) with no adjustments for yrs.Ran awesome.I just propped down when skiing.
Ski at Huntingon:bowdown: I did it once...tooooo cold for me!
 

Outnumbered

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I'm running an older 90hp Yamaha carb'd 2-stroke. We're headed to the Sierras next month for a few days and the lake is at 5500'.

I've been up around 4000' with no issues. Can't find my service manual so I thought I ask the o/b guru's on RDP.:thumbsup

Anything I can adjust to add air to the mixture (if needed)...?
is it oil injected or premix?
 

Faceaz

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It would. Injected engines won't load up as much at idle. As an example, some of the old OMC VRO set-ups lean out to nearly 100:1 with no load @ idle, then go to 50:1 when the engine is put under load. Premixing @ a constant 50:1 will tend to load it up a bit more because the engine can't cut back the oil with reduced load.

I never liked the VRO because it's mixing before it gets to the float bowls, so if you get on the gas from idle, there's a little lag time before the engine will adjust to 50:1. Then again, I just grenaded our motor a few weeks ago, so WTF do I know.. LOL...
 

SloWhacker

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I have also ran a pre mix 200 up here with no adjustments and no issues.:cool: Sorry bout your motor.:(
 

BajaMike

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I'm running an older 90hp Yamaha carb'd 2-stroke. We're headed to the Sierras next month for a few days and the lake is at 5500'.

I've been up around 4000' with no issues. Can't find my service manual so I thought I ask the o/b guru's on RDP.:thumbsup

Anything I can adjust to add air to the mixture (if needed)...?
If the motor has an air filter, make sure its clean or put in a new one. Also, I would buy a lower pitched, aluminum prop just in case you need to prop down.
 

shueman

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Thanks for the input y'all...:thumbsup Just had to postpone the trip due to some issues with the wife's work...:( Rental company was very understanding and will honor our reservations in Sept...:cool:
 
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