Why is one riser hot and one cold?

[CountryME]

So today I was winterizing my 2000 1900SR 4.3l Alpha 1 Gen 2 raw water cooling. While running it up to temperature to change the oil with the engine cover off to I happened to touch the PORT riser and then the STBD riser and noticed a significant difference in temperature between the two. The PORT riser was cool to the touch and the STBD was hot. While I had the thermostat housing apart it appears that the raw water is directed through the PORT riser first then circulates through the STBD after passing through the engine. Anybody know if I am guessing right on this or should I worry about a cooling blockage? The risers were replaced the year before I got the boat so I believe they are in good shape as I have put less that 50 hours on it since buying the boat and little of that was in salt water.

-JP

[seapuppy]

you are correct...the water flow is thru the port side and makes it's way to the stbd side removing heat as it goes......


I would concider running some salt away thru the system to clear out any possible salt build up...



SP

[CountryME]

Thanks for the validation SP.

[ccruser1]

Seapuppy,
What is saltaway and how is it used? I have power-boated in salt water the last 25 years and never heard of this.
thanks,
ccruser1

[shrew]

Here is a link to Saltaway:

http://www.saltawayproducts.com/

Good Stuff!

[dronthelake]

Not to throw a wrench in the conversation but I always thought the water went through the block first then to both exhausts manifolds at the same time. My manifolds have always been the same temp. My first guess is that the hot manifold is restricted with rust.

http://www.perfprotech.com/store/art...ling-tips.aspx

http://www.boatfix.com/how/cooling.html