Hello all, I just got back from a trip to 8000 feet and my recently repaired and gone over motor just wouldn't run worth a crap. I had a sea level mechanic work on it, and at sea level it was running like a bat out of hell. I am new to outboards but not 2 strokes. Anyways, while up in the high elevation I started to look at the carb and to try to find a air/fuel or fuel/air mixture setting, what I ended up finding are fixed sized jets located behind a lock down screw at the top of the intake throat of each carb. I pulled all 3 and located that I am running # 32 (straight 32, I've been told of 32a, 32b, etc, these are straight 32). Outer thread size is 5/32 (I'm going from memory at work, but I know to measure the outer threads because of different sizes for different slight variances on the carbs (the previous owner put a rebuilt 75 power head on it, but the carbs seem to be the original 73 65hp carbs.). From looking at online exploded views, my understanding is that this orifice located at the top of each carb (if looking at the carb while mounted with the air cover off) seems my PDF manual is calling this a orifice plug and screw plug). I originally thought this was air fuel mixture, especially since it looks like the air cover has a hole that should allow the screw plug and orifice to be accessed without removing the air silencer. (any help here?, is this low-speed) I thought I would need to get into the float bowl area to locate the high-speed?). I have a Evinrude repair/service manual on PDF, but its years 73-1989 (48-235hp) so it talks about them all and uses lots of "if yours is equipped with this, then do this"
Since I couldn't adjust the air/fuel for the elevation and it was running my vacation, I drove to nevada and was able to locate a shop where I purchased a 14" x 13 pitch prop, to replace my 13 3/4" x 17 pitch prop. This was enough to make the boat run 80 times better. I still had performance issues, and the motor WOULDN'T run at idle for very long, the slowest I could get it to stay running was at a gps speed of 3.8 MPH, no biggie, I tossed two 5 gal buckets off the back to slow the boat to trout trolling speed of 2.5 -2.7 MPH.
Anyways, with two weeks of messing with it, I would like to prepare myself for next year, I dont even mind buying an assortment of jets but have no idea what the 32's should be replaced with. I fish 4000 ft or so the most, but see a lake at 6000, another at 6800, and two at 7600 and 8000 ft. I know leaving it at 32's will protect me from getting to lean while at lower elevations, but I would like to have some help on say a size to try for 3000-5000ft, 5000-7000ft, 7000-9000ft. I also understand I have only seen the low-speed jet, but taking the carbs off the power head and dropping the float bowls to get to the high-speed no longer seems difficult to me know that I actually got into the carbs for the first time. Seems they can be taken off as a set and access to them can be obtained without having to disconnect linkage or anything.
Thanks in advance, I understand this could take quite a few posts. I welcome all suggestions as you guys are the experts.
-John
Since I couldn't adjust the air/fuel for the elevation and it was running my vacation, I drove to nevada and was able to locate a shop where I purchased a 14" x 13 pitch prop, to replace my 13 3/4" x 17 pitch prop. This was enough to make the boat run 80 times better. I still had performance issues, and the motor WOULDN'T run at idle for very long, the slowest I could get it to stay running was at a gps speed of 3.8 MPH, no biggie, I tossed two 5 gal buckets off the back to slow the boat to trout trolling speed of 2.5 -2.7 MPH.
Anyways, with two weeks of messing with it, I would like to prepare myself for next year, I dont even mind buying an assortment of jets but have no idea what the 32's should be replaced with. I fish 4000 ft or so the most, but see a lake at 6000, another at 6800, and two at 7600 and 8000 ft. I know leaving it at 32's will protect me from getting to lean while at lower elevations, but I would like to have some help on say a size to try for 3000-5000ft, 5000-7000ft, 7000-9000ft. I also understand I have only seen the low-speed jet, but taking the carbs off the power head and dropping the float bowls to get to the high-speed no longer seems difficult to me know that I actually got into the carbs for the first time. Seems they can be taken off as a set and access to them can be obtained without having to disconnect linkage or anything.
Thanks in advance, I understand this could take quite a few posts. I welcome all suggestions as you guys are the experts.
-John
Attachments
Last edited: