Water Jacket Descaling On A VMAX 150

[ggmizzou]

I have a 2000 VMAX 150 that overheats when running at top end. I've had all the suspect components replaced and still have the problem. When replacing the thermostats, noticed a lot of crud in the water jacket. I've been researching products to clean and it looks like many have had good luck curing similar issues by flushing with Rydlyme. However, I saw one post on a forum that indicated Yamaha's have anodes in the water jacket that must be removed before flushing with any type of acid solution. Hoping someone has some experience and expertise they can share on the subject. Thanks.

[BQUICK]

Cascade dishwashing solution with the thermostats removed seems to work well.

[ggmizzou]

Thanks for the information. Do you have any detail on concentration of the Cascade solution to mix and how long to flush? Planning to drop the lower unit and attach a line to the water tube to pump solution through the jacket. Will catch draining solution in the bucket and recirculate. Also, is the Cascade solution safe for anodes in the jacket? Thanks again.

[Tucker]

There have been a lot of success stories using vinegar as a flush. That's my plan when it ever gets above freezing here.

[BQUICK]

I don't know about the anodes. Sounds like a good idea dropping the lower unit and pumping solution thru.....
Sould be interesting to see how much scale you end up with in the bucket. Let us know....

[robert graham]

There is a product called "Saltaway", which is a mild inhibited acid for flushing motors. But any acid strong enough to remove say an 1/8" of calcium/salt scale would also be strong enough to attack aluminum parts. Maybe a good idea to remove exhaust covers and heads to see what you've got and to remove as much as possible mechanically, that would also reduce the chances of scale breaking lose and plugging up a passageway. I was many years in the water treament business and acid cleaned many boilers, but they were all iron and steel, so you could really pump the Muriatic acid to them without fear of dissolving much metal. A mostly aluminum outboard is more delicate. Good Luck!