Help with getting more power-135 HP Evinrude

[notyepcars]

I have a 1976 Hydrostream Vamp with a 76 evinrude 135 H.p motor. I have about 85-90 psi in all 4 cylinders so I'm looking at rebuilding. The boat is rated at 140 H.p, and i'm trying to gain some power if I'm going to rebuild this one. With this handle a newer 150 hp evinrude? Or what are some things I could be to my old one to gain some horepower. Thanks

[The Big Al]

Most Hydro's on this site have 200hp + High Performance engines on them.

[hsbob]

i had a older 150 [with the 175 carbs = newer 150] on a vamp. it did quite well. do not use any 4 bladed props thru. there's too much stern lift and it wont turn. ran in the low 70s with an older 21 omc SS prop.

the 135 can suffer from a poorly balanced crank. if your not into the low 60 that could be the problem.

there is a web between the two clclinder banks under the turner. at the centerline on the lower cylinders, cut away an inch long by about 3/4 deep slot. you now have a 140.

[EMDSAPMGR]

The 135 already included most of the modification potential for a V4. If you wanted more, you had to go to a V6. Any V4 changes will only yield minor improvements, but there are a couple of items: Bolt ons-Adding composite reeds improve any engine. When in there, I would add the intake filler blocks, found on the 140's-part # 322684. Machining mods: port the intake and exhaust. I would expect to see compression around 120+ on an overhauled V4. You may want to go direct to a V6. Still plenty of good V6 crossflows around. A good friend ran a 76 200 on a 15' Viper for years without problem, though he had a large aluminum plate on the back of the transom for support.

[racer]

a 76 135 should have compression near 150 stock.

[decoy033]

a 76 135 should have compression near 150 stock.

Your correct my 1973 135HP Rude has 145 - 150 PSI Know any mods for this motor?