# Boyesen reed valves



## flyclimber (May 22, 2016)

General consensus I have read online is in favor. What about you guys with first hand experience. 

Going in a 25 hp 2 smoker.


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## Guest (Mar 31, 2019)

Boyesen or Chris Carson, both are good.


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

Chris Carson r boysen, I have owned both, either work well. 2 Yamaha 2 stroke with boysen, 1 mercury efi 2.5 150 with Chris Carson. CC reeds performance was exceptionally good, GPS speed n idle much improved.


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## Plantation (Nov 24, 2015)

My buddy said it was one of the best upgrades he did for his 50 2s Yamaha. You need to sand down the reed block extra smooth before adding them. Use 600 grit and make sure no light is coming through after they are installed.


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

Plantation said:


> My buddy said it was one of the best upgrades he did for his 50 2s Yamaha. You need to sand down the reed block extra smooth before adding them. Use 600 grit and make sure no light is coming through after they are installed.


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

If u got little extra cash have the reed blocks surfaced n crankcase stuffer added.


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## flyclimber (May 22, 2016)

Plantation said:


> My buddy said it was one of the best upgrades he did for his 50 2s Yamaha. You need to sand down the reed block extra smooth before adding them. Use 600 grit and make sure no light is coming through after they are installed.


Where would I be sanding to make no light come through? The tips?


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## Plantation (Nov 24, 2015)

The way I understand it is the metal reeds that are on the reed block can push into the material they have been screwed into. For a 50hp 2s Yamaha there was a black material surrounding where the reeds were screwed into. On the Yamaha you can feel the intentions that the old reeds made. Need to make that flush so the new reeds sit without any lift or gaps. You can check by trying to see light through the backside of the reeds once screwed in. I'm no expert but just giving you the info as I've seen it done before. On other motors the reeds may be screwed onto straight metal blocks in which case you can ignore everything I've said. Once you take your reeds off it should be clear.


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## ek02 (May 8, 2012)

I had Boysen reeds on a 70 HP Evinrude 2 stroke many years ago. It ran well with them, but I never noticed any great power increase.


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## flyclimber (May 22, 2016)

@Boatbrains in the installation manual it says to flatten the mounting face of the reed block. I used a glass table and some 400 grit and got it to where about 50% of the rubber was kissed by the sand paper and 85-100% of the mounting surface (aluminum) was flat. Do you think that is enough? I am testing on the older motor until I get the new (used) power head in. The engine on the boat has some real pop too it now from down low.


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## Guest (Apr 8, 2019)

If your not seeing any or minimal blow back through the carb/s then they are sealing.


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## flyclimber (May 22, 2016)

Boatbrains said:


> If your not seeing any or minimal blow back through the carb/s then they are sealing.


Like backfire through the carb?


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## Guest (Apr 8, 2019)

freeclimber said:


> Like backfire through the carb?


No, but excessive fuel/air. You’ll see it if no air box on carb.


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## pbattleiv (Nov 16, 2014)

I had Boyesen reeds installed on a 2008 yamaha 2 cylinder 2 stroke. Also had head work done to increase compression. I also have the same motor completely stock. I can tell no difference in the two, performance-wise. The modded motor does, however, require premium fuel(because of the increased compression-not the reeds). 

The boyesen reeds work fine, but I didn’t notice any performance gains. In my experience, they provide no benefit over stock reeds on this particular motor. I think the two cylinder 25’s just don’t have a lot of easy hp gains to be had through modifications- now the 3 cylinder motors- that’s a different animal!


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## BudT (Jun 29, 2018)

Did exactly this on my 225 Merc, went with Carson reeds after having injectors flow tested and servicing fuel rails. What you are trying to accomplish is what BB has pointed to; the best sealing surface (w/o going through the rubber) so that the reeds lay flat on the sealing surface when the fuel mixture is not being drafted in. Also if no one has mentioned it consider removable loc-tite on the reed screws. I was very pleased with the improvement on my Optimax.


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## flyclimber (May 22, 2016)

I will let you guys know about the results, when I break from this weather. I think I may see some improvement due to the reeds that were in the block were lifted and worn out. I was actually able to get the engine to idle at a lower RPM and without having to reprime it. (not saying they were related by any stretch). 


BudT said:


> Also if no one has mentioned it consider removable loc-tite on the reed screws. I was very pleased with the improvement on my Optimax.


Already done!


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

pbattleiv said:


> I had Boyesen reeds installed on a 2008 yamaha 2 cylinder 2 stroke. Also had head work done to increase compression. I also have the same motor completely stock. I can tell no difference in the two, performance-wise. The modded motor does, however, require premium fuel(because of the increased compression-not the reeds).
> Had hydro tec kit + block ported
> The boyesen reeds work fine, but I didn’t notice any performance gains. In my experience, they provide no benefit over stock reeds on this particular motor. I think the two cylinder 25’s just don’t have a lot of easy hp gains to be had through modifications- now the 3 cylinder motors- that’s a different animal!


I had nearly the same motor n had great performance enhancements. Also had exhaust tuner, exhaust ported, carbs venturied n jetted.


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## flyclimber (May 22, 2016)

I finally had a chance to run it this morning and it felt strong! It popped right on plane! This is still with an older block. Haven't gotten the new power head back in.


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## BudT (Jun 29, 2018)

Glad to hear you think you are seeing performance improvements. I definitely saw smoother idle and more predictable acceleration through the power band.


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

Mercury racing using this type reeds, must be something to it?


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

Boatbrains said:


> Boyesen or Chris Carson, both are good.


I have owned both, excellent!


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## JC Designs (Apr 5, 2020)

Yes, I am torn for my 50 omc looper build! I am leaning towards the two stage boyesens but will call Chris before making my decision!


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

JC Designs said:


> Yes, I am torn for my 50 omc looper build! I am leaning towards the two stage boyesens but will call Chris before making my decision!


******** matter!


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