This may seem like a stupid question to some but I can't find it in my Manual. I have a 1985 90 HP Evinrude V-4 and I have no idea what the difference between a looper and a what ever else there is besides a looper?
1985 90's are cross flows. Do a search. The guys have posted meny very good, detailed explanations. It refers to the way the intake charge comes into the combustion chamber. <br /><br />Good luck!
By the way, it's NOT a stupid question. It shows you are looking for a basic understanding of your motor's operating principals before starting to work on it. <br /><br />Good move!!
The Looped locates the inlet & outlet ports in such a way as to prohibit the air-fuel charge from roaring through the combusion chamber - IE fuel charge comes in the inlet - through the combustion chamber & out the exhaust - due to the scavenging & inertia effect of the cross-flow. In a 4 stroke this is good thing as it increases the volumetric efficiency - in a two stroke it dramatically increases fuel consumption & emission - OMC invented the looped in the 60 's I think & patented it - I think .. Cross-flows also use those hoekey-assed pistons with the combustion chamber airdams to slow down the process just described. These pistons are characteristically heavier & more fragile than the loper pistons. HOWEVER< I ve heard the crossflow motors idle down & run better at low speeds .. So if trolling is you game .. I still would get the looper ..
