Boyesen reeds on a 1981 Johnson 70 hp?

water n oil

Cadet
Joined
Sep 20, 2007
Messages
18
Hey there again mates,

I have a 1981 Glastron SSV-151 16 foot openbow with a 1981 70 hp Johnson model J70ELCIH. I have the carbs off to rebuild them and was kicking aroung the idea of installing a set of Boyesen reeds since I have the carbs off. Would any re-jetting be necessary afterwards? What can I expect after installing them? Where is the best place to get them? Thanks for any help.
 

HighTrim

Supreme Mariner
Joined
Jun 21, 2007
Messages
10,486
Re: Boyesen reeds on a 1981 Johnson 70 hp?

I dont think any re jetting would be necessary. Their patented dual-stage design incorporates a specially shaped top reed and a ported bottom reed. The top reed is lightweight and resilient for crisp throttle response at partial throttle or low RPMs. The stiffer, bottom reed is ported to provide maximum flow and horsepower at higher RPMs. More valves equals more power. They are suppose to provide more air flow, more air velocity, and more overall power.

THE BENEFITS

• FASTER STARTS: No more sitting and cranking cranking when engine is cold or hot

• SMOOTHER IDLE: No more coughing, sputtering and dying.

• Blazing acceleration for that all-important holeshot.

• More horsepower throughout the powerband for guaranteed performance.

• Smoother Trolling: Troll down to a heartbeat with the controll of Boyesen Power Reeds

• Improved engine efficiency and fuel economy. Up to a 10% increase

• Longer Service life - Boyesen Power Reeds outlast all other aftermarket reeds.

Outboard dealers and service centers carry Boyesen Reeds, or you can buy them direct from their factory. Call Boyesen Engineering's toll-free number for assistance: 1-800-441-1177.

Never actually tried them myself, but Im sure others will jump in with their opinions. The benefits list was simply copied from their web page, not me trying to promote them ;) Good luck.
 

iwombat

Captain
Joined
Jul 12, 2006
Messages
3,767
Re: Boyesen reeds on a 1981 Johnson 70 hp?

If you read up on the boyesen site, you'll find a 3-5 size increase of the mains is normal.
 

Dhadley

Supreme Mariner
Joined
Feb 4, 2001
Messages
16,978
Re: Boyesen reeds on a 1981 Johnson 70 hp?

I think Boyesen recommends to richen up the idle circuit. That's basically to cover themselves if any particular motor spits back at idle. When a motor spits back or has a "lean sneeze" fire comes back into the intake and can burn the fiber reeds. There's only a couple of things that can hurt the Boyesens and the lean sneeze is the most common.

If it were mine I'd put them in while you're so close anyway. Some - not all - 49cid steel reeds can (it's rare) develop a strange idle symptom and the Boyesens will eliminate that possibility.
 

water n oil

Cadet
Joined
Sep 20, 2007
Messages
18
Re: Boyesen reeds on a 1981 Johnson 70 hp?

Thanks Dhadley,Wombat, And Hightrim for the help.
I went on the Boyesen site, but couldn't find anything where it talked about the main/high speed jet. I found this info on the FAQ page:

POWER REEDS

Q: Aren't Boyesen Power Reeds strictly for racing outboards?
Q: How come the leading bass pros don't endorse Boyesen Power Reeds?
Q: Can Boyesen Power Reeds harm my outboard?
Q: Are Boyesen Power Reeds easy to install?
Q: Can Boyesen Power Reeds help my older-model outboard run better?
Q: Can Boyesen Power Reeds improve performance on smaller outboards as well as those big V-6's?
Q: Are Boyesen Power Reeds guaranteed?
Q: I'm a commercial fisherman and depend on my outboard for my livelihood. Can I trust Boyesen Power Reeds in my engine?
Q: Where can I buy Boyesen Power Reeds?


Q: Aren't Boyesen Power Reeds strictly for racing outboards?

A: No! But because our reeds have been proven in thousands of hours of outboard racing, you can rest assured they'll perform great in your fishing outboard, no matter its horsepower. Boyesen Engineering has earned the title, "World's Leader in 2-Stroke Induction Technology." Let us put this technology to work in your outboard!

Back to top of page


Q: How come the leading bass pros don't endorse Boyesen Power Reeds?

A: Because the B.A.S.S. Tournament Trail* prohibits the use of anything but a box-stock outboard. But if you're among the thousands of bass boaters who don't fish the pro circuit, you can enjoy the smoother idling, faster hole shot, increased acceleration and improved fuel economy that only Boyesen Power Reeds can deliver!

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Q: Can Boyesen Power Reeds harm my outboard?

A: Absolutely not! In fact, Boyesen Power Reeds are safer in your outboard than stock metal reeds. If a metal reed breaks, it can destroy your engine. But should a Boyesen Power Reed fail, due to its glass and epoxy construction it would go through your outboard like paper through a shredder, causing no damage to your engine's expensive internal parts.

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Q: Are Boyesen Power Reeds easy to install?

A: Anyone with a little mechanical aptitude and hand tools can install Boyesen Power Reeds, or your outboard mechanic can do it for you at a reasonable price. Plus, Boyesen Engineering has a toll-free number and technicians on duty to answer any installation questions or offer assistance.

Back to top of page



Q: Can Boyesen Power Reeds help my older-model outboard run better?

A: Over time, stock metal reeds can become worn or frayed, resulting in a loss of crankcase pressure and a decline in performance. Installation of Boyesen Power Reeds, together with a fresh set of spark plugs and gaskets, can make your older outboard run better than it did when it was brand new. No wonder fishermen tell us, "Boyesen Power Reeds breathe life into tired outboards!"

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Q: Can Boyesen Power Reeds improve performance on smaller outboards as well as those big V-6's?

A: Y ou'll feel the difference in every outboard, no matter how big or small, when it's equipped with Boyesen Power Reeds! We manufacture the right reeds for most outboards from 9.9 to 300 hp. Smaller outboards equipped with Power Reeds idle and troll more smoothly, burn less fuel and have more punch when you bury the throttle. It's technology every fisherman can appreciate!

Back to to of page


Q: Are Boyesen Power Reeds guaranteed?

A: Yes! Boyesen Power Reeds carry a written one-year warranty from date of purchase. If our reeds fail, and it's our fault, we'll replace them free - it's that simple! (Race boats and improper installations are excluded.)

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Q: I'm a commercial fisherman and depend on my outboard for my livelihood. Can I trust Boyesen Power Reeds in my engine?

A: Boyesen Engineering guarantees Power Reeds for one year from the date of purchase, even in commercial fishing applications. Your Boyesen-equipped outboard will perform more efficiently, deliver significant fuel savings, and help you do your job better over the long haul.

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Q: Where can I buy Boyesen Power Reeds?
 

iwombat

Captain
Joined
Jul 12, 2006
Messages
3,767
Re: Boyesen reeds on a 1981 Johnson 70 hp?

Maybe it was the mids that I'm thinking of. I did one years ago and remember replacing jets. I also read it pretty recently, since I'm planning on doing my crossflow sometime over the winter. Some jet went up 3-5 sizes - I swear it!
 

guy74

Senior Chief Petty Officer
Joined
Jul 12, 2007
Messages
794
Re: Boyesen reeds on a 1981 Johnson 70 hp?

The instuctios with the boyeson reeds I have for my 60hp say to downsize the idle air jets by 5 sizes or 5 thousandths on an inch. I bought a set for my 60hp but then I replaced the motor with a bigger one. So I have a set of reeds that should fit your motor if your interested.I got a pretty good deal in the ones I have.
Good luck,
Brian
 

water n oil

Cadet
Joined
Sep 20, 2007
Messages
18
Re: Boyesen reeds on a 1981 Johnson 70 hp?

Thanks Guy,

I called the tech line on the website and the guy I spoke with said the same thing " go down 5 numbers/thousandths on the low speed air bleed/jet to richen the mixture".

On my particular carburetors there's the high speed main jet located in the carb bowl, the Off idle orifice located at the top of the carb under a screw and gasket, and the low speed orifice located close to the base of the carb at about a 45 degree angle to the base. The numbers are as follows:

High speed - 52 D

Off idle - 37

Low speed - 55

So I would need a #50 low speed orifice. Anyone know if these are readily available? I looked up on the BRP website ( Thank you TD ) and the numbers of the orifices don't match the ones I have except the high speed. Any ideas?

Guy..I also sent you a PM on your reeds. LMK.

Thanks again!
 

iwombat

Captain
Joined
Jul 12, 2006
Messages
3,767
Re: Boyesen reeds on a 1981 Johnson 70 hp?

Ah yes, I forgot about that little nuance.

The earlier carbs go up in size to richen, the later ones go down to richen.

Silly me.
 

mikesea

Lieutenant Commander
Joined
Oct 1, 2006
Messages
1,830
Re: Boyesen reeds on a 1981 Johnson 70 hp?

FYI,when I rebuilt my early 90's 70,I had to go down in size in ,if I recall was the air jets,which may be what are called off idle jets by poster water and oil,I seem to remember the size was in the 30's and I soldered them,redrilling until I idled ok.I worked for a powerhead rebuilder and when we went oversize pistons on some 3 cylinders carb.tweaking was needed.
 
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