your experience with cleaning cyl heads and water jackets for corrosion

[newatthis]

1993 200 hp overheats after about 4000 rpm's, buzzer goes off.

Yamaha tech took boat out and at 5000 rpm's alarm goes off, checked engine with infrared thermo and got 141 at base of engine.

Tech says engine needs passages cleaned.

What is everyone's experience with this, would you do this at a beginning or intermediate level?

Just thinking about one corroded bolt makes me stop and ask how easy is this?

Cleaning after getting the cover off, , seems like I would enjoy cleaning out the engine just knowing how much better it would run.

So if you have tried this succedfully or not, what should I look for?

There are a lot of threads abouth this so I was wondering if someone has something new such as what is the best way to take all those bolts out? and what if one bolt breaks off

let us know

Thanks,
very Newatthis

[newatthis]

should of mentioned

brand new water pump, new thermostat's, and new poppet valve installed.

pee stream is very good,

[BQUICK]

I pulled the heads and cleaned. Fixed the problem. Looked like stuff was living in there! Red and yellow growth as well as calcium deposits. (Florida motor) Only one cover bolt broke. Left it out.....

You could try aggressive flushing with muriatic acid or white vinegar.

[cool rock daddy]

I pulled the heads and cleaned. Fixed the problem. Looked like stuff was living in there! Red and yellow growth as well as calcium deposits. (Florida motor) Only one cover bolt broke. Left it out.....

You could try aggressive flushing with muriatic acid or white vinegar.

sounds like mud dobbers again,read another post about them building nests up thru exhaust system

[newatthis]

what did do you do before loosening the bolts

spray (wd-40, PB Blaster, CRC etc), if so what method? let it sit for 15 minutes, an hour?

How many bolts can you break off and still be okay?

I'm thinking to maybe try and see which one's I could loosen without much force first, since I changed the thermostat i would have a point of reference to how much force I should use to break the bolt free.

Does this make sense?

[Pro liner 61]

Cleaning water jackets and heads

Just finished taking my heads of twin 150 Yamaha outboards due to over heating issues even after installing new pumps, thermos and using saltaway. The jackets were very clogged and while I'm there I decided to also clean the heads. Very important to use metric tools when removing bolts. All were coming off easy until I used the wrong socket and broke two Bolts. Do not think you can use special tools to take out the bolts. They are corroded with salt and needs to be drilled and re-tapped. Aluminum heads do not need to be resurfaced, take them to a marine shop for some simple cleaning and light surface sanding. Now you ready for reassembling the heads and jackets with new gaskets. Remember to torque in order and to specification using some lube on the threads.

[BQUICK]

I broke one of the lower bolts off and couldn't get to it to drill out due to the apron. It leaked from the area with the missing bolt. I ended up putting a Vicegrip plier where the bolt was and no leak. Just finished my third season on it.