3/8 Pisser & Flow Control Valve on JS440?

[brapperdoodle]

My brother ended up with a super mint 1 owner 1990 JS440, it has a really nice KERKER pipe on it and a standard cooling set up with stock pisser and no FCV. The cooking lines are 3/8 but the pisser line is 1/4. Is there any reason I would not want to run a 3/8 pisser line and FCV? I have extras laying around and want to put them on this ski but I don’t know if there is a reason the stock pisser is 1/4.

 

[brapperdoodle]

 

[brapperdoodle]

Can anyone direct me to general information on cooling? I hear a lot about dual cooling etc. but I’m trying to understand the basics

 

[joelake]

Dual cooling is 2 lines from pump to exhaust manifold instead of 1 line (single cooling). You would need a exhaust manifold that is tapped for 2 barb's to run dual cooling, and if you have 2 cooling lines in to the engine, you need the same or more out of the engine to take advantage of the extra volume of water coming into the engine.

Cooling usually starts at the exhaust manifold runs thru the head and out into the head pipe, then overboard/ tee off into exhaust. What your last pic shows seems pretty legit to me. You need to make sure the FCV is dumping the correct amount of water into the waterbox. Not to much, but not to little.

I have seen a pic of a Yamaha based engine that has dual cooling, where 1 line went into the exhaust manifold, and 1 to the head. This to me seems a bit strange as the flow would have a stagnant area somewhere between the 2 inlets, unless there was an outlet somewhere in between, but that would make little sense.

Dual cooling is not 100% necessary in stock or mild mod application. It can be a detriment of you live in a cold area also.

I am no real expert, but that should help you.

 

[wmazz]

You need better priorities. At this point your 440 is a good kids, or a
wimpy girl ski. Unless your brother is a lightweight, you need to
concentrate on parts that will help the ski come out of the hole.

More power will make it more ride-able. That exhaust manifold
needs to be replaced and you need to verify the compression, and
what impeller is used.

Don't worry about dual cooling for a long time. But if you ever get
to that point, do what we used to do when 440 super stocks were
popular. Install a single 1/2" ss cooling line.


Bill M.

 

[brapperdoodle]

You need better priorities. At this point your 440 is a good kids, or a
wimpy girl ski. Unless your brother is a lightweight, you need to
concentrate on parts that will help the ski come out of the hole.

More power will make it more ride-able. That exhaust manifold
needs to be replaced and you need to verify the compression, and
what impeller is used.

This is a kids and girls ski. Thanks.

 

[wmazz]

Does it have a SS impeller?


Bill M.

 

[wmazz]

The stock exhaust manifold tends to foul spark plug on the rear cylinder
because the cold water enters the rear of the exhaust manifold.

Doubling up the carb base gaskets on the top and bottom of the throttle
cable mounting plate will improve starting reliability by preventing a common
vacuum leak.

Bill M.

 

[brapperdoodle]

The stock exhaust manifold tends to foul spark plug on the rear cylinder
because the cold water enters the rear of the exhaust manifold.

Doubling up the carb base gaskets on the top and bottom of the throttle
cable mounting plate will improve starting reliability by preventing a common
vacuum leak.

Bill M.

That could very well be one of the issues I am having with this ski. It seems to start and run for about 30 seconds and then runs horribly, only staying running if you give the ski WOT. It won't rev though, just barely stays running with wide open throttle. The cooling parts were only because I had extras laying around and figured they would work for this 440

 

[wmazz]

Sounds like an exhaust or fuel leak.


Bill M.