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3.5 Rossi Heads

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3.5 Rossi Heads

Old 08-10-2006, 10:41 PM
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chuck731
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Default 3.5 Rossi Heads

I just pick up a Rossi 3.5 powerhead cheap and its new. The engine does not have any
paper work or info so I'm kinda lost. It came with two heads, one flat around the hemi head and the other is concave around the hemi head. Is the flat head for higher nitro?
Also what is a good head clearance to start with running 60 percent. Its at .014 now. The engine is a 68 R 21 outboard powerhead. I have been running K&B's so I know nothing about this motor. My fingers are crossed.
Old 08-10-2006, 11:24 PM
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Ron Olson
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Default RE: 3.5 Rossi Heads

Check to see if one is for cone-lock (turbo) glow plugs. My Rossi came with the cone-lock chamber insert but I heard that they made one also for regular plugs.
The high nitro head may have a dot somewhere on it like a tiny drill mark but can't say for sure.
I love my Rossi but keep in mind that they seem to take forever to get broken in so don't be disappointed if it runs like crap for a while, it may take a gallon or more before it wakes up. Restricting the water flow just a little helps to get more power out of them as they seem to like the heads warmer.
Old 08-11-2006, 01:15 AM
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chuck731
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Default RE: 3.5 Rossi Heads

Ron, Both heads takes a standard plug. On the head that is concave it has a "n' stamped on top. Would that be for higher nitro?
The concave head would have less volume and maybe for th higher nitro. I have no idea what you are talking about then you say cone-locked head. I run a keeley on my K&B. Are we talking about almost the same idea.
Old 08-11-2006, 02:02 AM
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oldlugs
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Default RE: 3.5 Rossi Heads

I believe that the higher volume head should be for higher nitro. A cone-lock plug has a tapered seat, like many automotive spark plugs now have. The cone-lock style is also known as a "turbo" plug; not related to the Keeley "turbo" head on your K&B though.
Old 08-12-2006, 03:18 AM
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poobee
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Default RE: 3.5 Rossi Heads

I have a question what is the HP from a Rossi 3.5 outboad about... ?
Old 08-12-2006, 08:29 AM
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Ron Olson
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Default RE: 3.5 Rossi Heads

2.9 to 3.1 HP according to them, 38,000 RPM.

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