Magical Recirculation hoses and valves....

[Fl_Richard]

I've been working on my 150 1995 engines for several years with lots of help from iboat members. I feel I now have a pretty good understanding of what does what and when there is a problem where to point the foam finger. I've successfully rebuilt one of two and it runs like a bat out of HE double hockey sticks.

The other motor is not running as good as it should. I've tested spark, timing, compression and re-built the carbs and replaced the reeds last year. From what I can tell everything is good.

One thing I've never understood is the recirc system. I know it scavenges unburnt fuel from the crankcase but if it's not working right what are the symptoms? Does it affect operation? If so at idle or WOT or across the band?

This is about the only thing I haven't looked at and I'm wondering if it needs a closer look. The hoses all visually look OK but they are 14 years old...

Many thanks again gentlemen!

Richard

 

[ezeke]

Re: Magical Recirculation hoses and valves....

If the valves stick closed, the oil builds up and the engine smokes at start-up more than it should and the engine runs a little rougher at idle. If the valves stick open, you could have air flowing in the wrong direction.

My 1970's motors never had them, but I noticed the difference when they are working correctly.

When I de-carb the motors I have to pull the check valves and soak them in SeaFoam or alcohol to get the carbon out or they stay closed.

 

[Fl_Richard]

Re: Magical Recirculation hoses and valves....

Thank you ez

Looks like I can ignore recirc system for now. My problem is les than full output at WOT. It will only rev to around 3200 by itself. With it's mate helping it will go to 4000 while it's mate is doing 5800. It used to do 5800 without a problem.

Thanks again. I'm going to find this problem eventually I'm just a litle stumped.

 

[ezeke]

Re: Magical Recirculation hoses and valves....

I would put an inductive timing light on the sparkplug wires one at a time and let somone else drive while I observed the flashes.