Question for the experts on cooling system

[Jason2tpa]

Have had this setup for nearly three years and has been flawless

Ah ha, more info surfaces. Operating engine three years with the same impeller and stats...either component, or both components, is likely the issue. Even more likely if your engine is operated in saltwater.

Like others have suggested, start with removing (or preferably replace) stats. And while you've got the top cowling of, check to see how the PCV looks. If issue persists (and even if it doesn't), replace impeller.

[TownsendsFJR1300]

Never seen that brake caliper seal maintenance reference before Scott. That seems way overboard to me...The only time I every knew anybody, including myself, to change brake caliper seals is when there was evidence of leaking.

Dirt bikes and Quads are mostly what I have seen with leaking brake calipers and I suspect that is the result of running in the dirt and muck all the time.

That come from your Bike manual?

The front calipers on my bike are each 4 piston calipers. I've NEVER had them leak.

The issue (same as with my old FJR1300) is the rubber seals harden and don't retract fully
resulting in dragging brakes(which can get really bad). As noted, in real life, I get 4-5 years
before the seals need changing. For each "hole", there's the main seal and a dust seal.

Here's a link for my front brakes to give you an idea: https://www.partzilla.com/catalog/ya...-brake-caliper

(Partzilla IS Boats.net BTW. I can order bike and boat engine parts on the same order)


Below is from my shop manual.


Master cylinder seals and caliper seals, EVERY TWO YEARS..:

Notice they also want brake lines replaced every 4 years?

[pstephens46]

The front calipers on my bike are each 4 piston calipers. I've NEVER had them leak.

The issue (same as with my old FJR1300) is the rubber seals harden and don't retract fully
resulting in dragging brakes(which can get really bad). As noted, in real life, I get 4-5 years
before the seals need changing. For each "hole", there's the main seal and a dust seal.

Here's a link for my front brakes to give you an idea: https://www.partzilla.com/catalog/ya...-brake-caliper

(Partzilla IS Boats.net BTW. I can order bike and boat engine parts on the same order)


Below is from my shop manual.


Master cylinder seals and caliper seals, EVERY TWO YEARS..:

Notice they also want brake lines replaced every 4 years?

Covering their ass.......Nissan directs me to flush my brake fluid in SUV every 15000 miles. That would be every 6 months for me....Nope.

[TownsendsFJR1300]

Covering their ass.......Nissan directs me to flush my brake fluid in SUV every 15000 miles. That would be every 6 months for me....Nope.

Correct, that's what I said. Yamaha, by the book, is very "aggressive"(probably not the right word).

If you followed the maintenance procedures to the letter, (marine/bike, etc), the machines, and dependability would last forever, be increased...

[dngharvey]

1998 Yammie 115 two stroke. Had it running on the trailer to get ready for storing and noticed that one cyl bank never got very warm at all while the other was hot to the touch. ( you could keep contact so not real hot ) The pee stream also did not get warm, water coming from the prop was lukewarm and plentiful.
Ran it for probably twenty minutes, should have been plenty of time to reach operation temp. Headed for the keys in January and want to be as ready as possible.
Time to change the t stats? Mainly a fresh water boat but flushed faithfully when in warm Florida waters.

Follow up on this question. One t stat stuck open and one stuck closed, glad I followed thru. Also had the impeller replaced and a go over, all good and told nice and clean inside.
Thanks much for the help, as always.

[TownsendsFJR1300]

Thanks for the update...

Just as an FYI, I'm in SW Florida, brackish / salt water.. I flush religiously after every use-running on muffs till hot / thermostat open.

Didn't have any cooling issues but during maintenance, found a bit of SALT BUILD UP on the T stat, PCV spring, etc. Replaced everything just because.

It's my belief, that you run the engine to say your fishing spot and turn it off. Salt water drains from the hot block, some salt remains and cooks / adheres to the block.

Years (even flushing) of on /off (normal use), salt / corrosion WILL cause build up / corrosion...