Modifying a 1990 20hp 31.8 cid
I have already changed the Carb and done some porting. I am looking for more hp, what are the best trick/tips to achieve this and does any body have any advice on the tuner (how should it be modify).
Modifying a 1990 20hp 31.8 cid
I have already changed the Carb and done some porting. I am looking for more hp, what are the best trick/tips to achieve this and does any body have any advice on the tuner (how should it be modify).
hey, some how i'm seein a crossflow motor, but that may not be right, got a shot of the powerhead
Part one of "Secrets of the OMC Mod 50" : http://www.boatracingfacts.com/forums/showthread.php?t=2052
Ya your correct its a crossflow engine. I will try to get some pictures up tonight.
Crossflow 35 hp motor with the carb from the 35. Mike Petty
bmh20h@att.net
is the expert. Here's a photo of one of his 31.8 ci OMCs.
He runs Mod C against Yamahas.
Emustard...what boat are you running? Got any pics of your mods? What about raising the compression?
Jason
Outboard Junkie
I am running this engine on a 14 foot aluminum princecraft. I am currently in the Process of porting so I do not have any pictures. I am looking for a high compression head at the moment but can't find one anywhere, so will probably end up making one.
Ya I have been looking for one for a while and have not seen one. My rig weighs 275-300 lb boat alone with engine and gas tank 450 lb. 13x10 pitch aluminum OMC prop 32mph @ 6200RPM ( I can put 5 people in the boat and we slow down to 29mph) with a 15x10 pitch stainless solas prop 33mph @ 5500 by my self (two people in the boat 32mph @ 5300). I do not have porting specs.
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