99 40 hp johnson mods

[OUTBOARDER]

With the 12.75x15 I'm turning 5750 rpm so I think the 19p prop would be good if I I'm not satisfied I'll get it worked from my research they do not make a 21p prop for a small gearcase the biggest I found was a 19p

Brand New OMC BRP 391014 in box. Aluminum prop 11.25" x 21 P

Fits: JOHNSON EVINRUDE - TWO CYLINDER, SMALL GEARCASE;

40HP (1984 THRU), 48HP (1987 THRU), 50HP (1975 THRU),

[Kevodaniel]

Thanks for the part number I finally found it earlier this morning I come across a stiletto triad 2 in a 11.75x19 stainless prop for $208.95 at firstchoicemarine.com

[Kevodaniel]

Did a test run today 50 hp carbs really helped out and I raised the jackplate 2in @ 6000 rpm it runs 35 now I'm just waiting on a prop I have a 12.25x15 goin to a 11.75x19 so hopefully it will break the 40 mph mark and get my rpms down to 5500

[OUTBOARDER]

Did a test run today 50 hp carbs really helped out and I raised the jackplate 2in @ 6000 rpm it runs 35 now I'm just waiting on a prop I have a 12.25x15 goin to a 11.75x19 so hopefully it will break the 40 mph mark and get my rpms down to 5500

the 21p @ 5500 was 40 mph on the carolina skiff 11% slip , rig weighd about 900 lbs.

[Kevodaniel]

Just me in the boat weights 650lbs. it done 33 mph @ 5750 rpm with a total weight of 1150 3 others in the boat

[Xpress2830]

The 40 / 50 exhaust tuners have different p / n's. Has anyone modified a 40 tuner ??

[Xpress2830]

The 40 / 50 tuners have the same p / n 's. has anyone modified a 40 tuner ??

[Lil' Blue Rude]

I've done two on the 89 up 40hp. From 89-up on both the 40hp and 50hp the tuner and the plate the powerhead bolt to are one cast piece along with the pick up for the water. So you have to cut the exhaust off leaving the water tube in tact and then weld on a new exhaust tuner. Normally a cowbell style tuner like a 45ss or a SST60 has.

[Xpress2830]

I've done two on the 89 up 40hp. From 89-up on both the 40hp and 50hp the tuner and the plate the powerhead bolt to are one cast piece along with the pick up for the water. So you have to cut the exhaust off leaving the water tube in tact and then weld on a new exhaust tuner. Normally a cowbell style tuner like a 45ss or a SST60 has.

Thanks for the info Rude. Couln't I just cut tuner just above the nipple at the bottom all way across to relieve the exhaust and call it good? Looks like alot of restriction there.Is the 50 head with reeds and carbs gonna get me close to the 50 - 55 hp window? If I not due you have a moded head that will help. I have this motor on an Alweld 1548 semi V. I want to keep the motor reliable not for racing. Thanks, Bobby...If you have a chance give me a call. 337-764-5534Attachment 59143

[Lil' Blue Rude]

I think by the time you get he 50hp head and plug your idle relief hole your compression will be high enough I'm not sure you'll be able to go any higher on 87 pump gas.