Bought a boat this winter, has 540's with a crossover with bypass and no thermostats. Drove the boat a couple times already and runs perfect but runs a little too cool.110 degress . Motors have water dumps that go from the front of the intake thru the transom and dump outside. I decided to try some thermostats to heat it up a little and while running on the hose water would only come out the dumps and not exhaust. Was thinking it was easier path for water to go out versus going through the exhaust. I only ran it for a minute or so. I thought having a bypass water should always go through and cool the exhuast. Was wondering what the real reason is for these dumps and if their really needed. If i plug dumps will the water then come out the pipes? Thanks for any help. Jason

hey jason,
you may want to put 140 thermostats in and drill 3, 3/16 holes in them. sounds like the water temp probably didn't get high enough to open the stats in which case did not allow water flow through the exhaust. not sure how your set up is plumbed. i am going to run water dumps on my 496's. my dart intakes are drilled and tapped at the rear water jackets and joined together with a tee and then dump out the back however I am going to install a gate valve near the transom to regulate the amount of water being dumped as well as hopefully be able to build some heat by resticting the flow and also to help regulate water pressure. kind of a trial and error thing. not saying this is the correct method but...

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Thanks getrdunn. I thought drilling holes was only to let steam pockets out . With a bypass shouldnt water being flowing through the exhaust at all times even with the thermostats closed?

Jbraun2828,

you are correct you should have water going through your exhaust if you have a by pass running from the crossover pipe to the thermostat housing above where the thermostat is placed

Cliff

Can you post a pic of your set up so we can see the hose routing and type of crossover and housing you have. You should have a hose going from your crossover to your stat housing which will get water to your exhaust. You are correct in regards to your other assumption.

What is the min size hose you should have going from the crossover to the stat housing?

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Anyone??