45ci OMC twin mods

[Kevodaniel]

Does anyone know how to adjust timing I have a 99 40hp johnson with boysen reeds and 50 hp carbs factory is 18 degree the 50hp was 19 thanks for any help

[Powerabout]

Does anyone know how to adjust timing I have a 99 40hp johnson with boysen reeds and 50 hp carbs factory is 18 degree the 50hp was 19 thanks for any help

http://www.outboardbooks.com/
PS I would shave the head to sst45 spec first.

[Kevodaniel]

The 2000 50 Cylinder head can be milled to 45spec 0.515" deep, stock is approx 0.560" worth about 5 hp and will run on 93 octane pump gas.
You can go up on timining , the 60hp twins ran 21 deg from factory.

Carbs are 1.5" throat x 1.25" venturi same as 75 triple an sst 60. you can remove the factory air box from carbs and pick up about 200 rpms on top end with noticable loss of 3500-4000 midrange power. Tim Kurtz has velocity stacks and they will help top end if your not over proped. will need to go up a step or two on main jets. Boysen makes reeds for the 50 and 45ss.

a 45 style tuner can be made to adapt and replace inner exhaust. I would go longer than 45ss spec to not loose bottom/mid tourque.
also can re-route water in conjunction with tuner mod to feed engine from bottom up and get water to be about 140 deg F under WOT.

Bobs Machine makes a nosecone/low water pick up for the gearcase.

run more oil OMC recomended 25:1 for the 45ss.

How would you advance the timing on these would a timing light work as far as milling the head is that measurement from the bottom of the dish were the spark plug goes to the deck