crossflow v6

[capngregorus]

Hey, just wondering the main function of the vacuum hoses between the viewing windows and the intake ports, (they go between 1-2 2-1 3-4 4-3 5-6 6-5) on the old crossflows.. I assume they are for some kind of scavenging..

Maybe pulling unburned fuel from the bottom of the cylinder and putting it back in the intakes?

Mine were all gummed up.. Could they effect a compression reading?

 

[emdsapmgr]

Re: crossflow v6

It depends on what year your crossflow is. When OMC first came out with the cold-start fuel primer (around 1980,) some of these early, early models injected that extra fuel direct into the intake side covers via a hose system. By 83, they added brass fuel barbs on the top of the carbs and injected this extra fuel that way. Later models came out with another system, called the recirculation system. This is probably the system you have. The intent is to scavenge excess fuel (at idle) from behind the reed boxes and transfer it into the combustion process. This system was not available on the early crossflows-only the later models. These hoses had various routings over the years, but basically went from the intake manifold to the intake side covers. I doubt you will see any real compression differences if the one-way valves in that system have become plugged and have quit functioning. My concern would be when those hoses start to deteriorate/leak and fuel/oil leaks onto the engine under the cowling. It's slightly messy, a fire hazard and may cause a very slight lean condition.

 

[capngregorus]

Re: crossflow v6

thank you very much, it might help me determine what year it is since it can't be found anywhere else on the engine.

 

[emdsapmgr]

Re: crossflow v6

If the model/serial tag ever goes missing, there is a casting plug on the top of your block which usually is stamped by the factory with vital information about the engine. It is probably painted over on your engine. The information on the later models is a little more obscure and you may have to dig to find out what it means.