Different size jets?

[kenboyd]

Are different size jets ( high & low speed orifices) available for type 1, single barrel, Evinrude carburetors? If so, where can I get them?
I have a 1989 70hp Evenrude I would like to lean out a bit, after installing Boyeson Power Reeds.
Thanks, Ken

[sst45jefff]

Yes - at the dealer.
probably wont help you though unless there is a ton of humidity and it was not jetted right for the area to begin with.

[Sam La Banco]

Don't believe the size stamped on them, because their not.

[kenboyd]

Thanks for replying, Jeff and Sam. I had gotten some similar answers yesterday at forums.iboats.com. I thought re-jetting would be as simple as it was on motorcycles, mopeds and go-karts, which I've done a lot. But I have found that different size jets are not as readily available for outboards.
My plugs are a little darker than I would like, but for the sake of longevity I'm going to leave the jets alone for now.
By the way all, regarding the dimples on a golf ball. The reason golf balls have dimples is to produce a boundary layer so that it moves through the air with less drag. As the ball spins, the dimpled surface causes the air molecules to attach to it. This produces a layer of attached air rotating with the ball. This creates the effect of a ball of AIR moving through the air mass. There is less resistance between the two air masses so the ball flies relatively true. If the ball were smooth it would become more 'sticky', similar to the back of the spoon under the water from the faucet phenomenom.
Water and air are BOTH fluid mediums they react to movement in the same way relative to their density diferences. The reason I know these things, is because I have been hang gliding since 1978. In hang gliding reduction of drag if paramount. We have measurement figures for such things as coated or uncoated wires of varying diameters. Enough for now.

Ron, I want to buy another prop from you. Two inches less pitch. I'm making a video of my boat for you. I'll send it in a week or so, with all the numbers you will need to make me another nice prop. This 12 5/8 x 30 has 10% slippage. Not too bad for right out of the box, with no reworking. My wife thinks I'm strange, because I sometimes just stare at it for minutes at a time. A beautiful propeller indeed! Thank you.
Ken Boyd

[OUTBOARDER]

The SST-60 Cat calls out for 73D the jet size is stamped on the jet.

[Fastjeff57]

What ever you do, don't let anyone try to talk you into making up adjustable main or idle jets for those carbs. I used ONE of those carbs on a Merc 25 project motor and spent all summer getting the adjustment to work properly--and that was one carb!

Jeff

[kenboyd]

What ever you do, don't let anyone try to talk you into making up adjustable main or idle jets for those carbs. I used ONE of those carbs on a Merc 25 project motor and spent all summer getting the adjustment to work properly--and that was one carb!

Jeff

Thanks Jeff. I'm familiar with adjustable jets. We use them in ultralight aircraft to maintain a proper mixture with altitude gain. It's best to use them in conjunction with an EGT gauge.
I don't plan on messing with my jets anytime soon. Tomorrow I'm going to put in a new power pack and impeller, then do some more testing when the wind dies down. As I mentioned above, I'm trying to get some accurate data to give to Ron, so that I can have another prop made.
Everything I'm doing on this boat now (12 foot sport c tunnel boat), is temporary. I can't really go the speeds that I want, with this gear ratio (2.42). I just located a new leg with a 15 inch shaft and a 1.866 gear ratio. It has a coarse spline, so I'll have to splice a fine spline to it. When I can afford to buy it, I will be dealing with a totally different beast.
Ken

[OUTBOARDER]

Doing the same thing with clydes ride, have two of the 15/28 nitro cases and will cut off course spline input shaft above water pump housing, mill flats on end then use the 1/2" stainless coupling to adapt to a fine spline drive shaft from a 45 or 60 crank.

[kenboyd]

Doing the same thing with clydes ride, have two of the 15/28 nitro cases and will cut off course spline input shaft above water pump housing, mill flats on end then use the 1/2" stainless coupling to adapt to a fine spline drive shaft from a 45 or 60 crank.

It looks like I may be doing my gearcase conversation sooner than expected.
I took my boat out this morning, testing a 3/4 inch lower, engine height change. After cruising it around a little bit to warm it up, I got on it hard. After about a quarter of a mile, I started feeling a heavy vibration. I slowed down and it got better, but as soon as I got on it again, it got really heavy, then the engine stopped. I tried to restart, but it was frozen. Dollar signs started flashing before my eyes.
Luckily I was only about 50 yards from the ramp, so I took everything that I didn't want to get wet and put it in the seat, then I eased into the cold 70 degree, shark infested waters of Keehi Lagoon. (Just kidding about the cold, and the sharks USUALLY stay outside the reef.) I side stroked back to the ramp, pulling the boat behind me, holding the bow line with one hand. After about 15 minutes of battling a stiff breeze and a mild current I arrived at the boat ramp.
When I got the boat out, I pulled the spark plugs and tried to turn the engine over with a wrench. Something was stuck, but with some back-and-forth movement it came free. I cranked it and it cranked smoothly.
I hooked up the water and started it. It ran fine, but I did hear an intermittent clanking in the gearcase, even though it was a neutral.
I'll take it apart later today to see what the damage is.
At least I got some excitement and exercise this morning. At 62 years old, I need to take it when I can get it.

[Bill Gohr]

Jets. are commonly available, the size and part number are listed on the last page of section 1 in any service manual, (we made sure of that), most dealers won't bother to look, and they are all marked, Sam, put on Jerry's glasses.

As far as the GC spline thing goes, if you're going through the pwerhead why don't you just change the crank, it's easier..............

[John (Taylor) Gabrowski]

I have 9 spare OMC carbs for 3Holer 49 inchers here to spare outside of what there is for the motor. Being a high speed needle tuning freak who loves to tune with test wheels, tachs and temperature sensors I would sure like to know if one can successfully change a tripple set to high speed hand twistable needles instead of fixed jet inserts to do the tuning? Anyone handy can do that sort of conversion but does the carb really lend itself to it to begin with as some carbs due to their design engineering just don't? Anyone have the experience posting to this question will always be appreciated.