Inspecting cylinder head cooling passages

[DennisG01]

Please correct me if I'm wrong here... I am thinking of inspecting the cylinder head cooling passages (for salt) when I get back to the boat in a month. Am I correct that I only need to remove the cylinder head COVER and it's gasket? Meaning, there is no reason to remove the actual cylinder HEAD, itself? Just planning ahead as I will go on the assumption that the cylinder head cover gasket will become un-reusable after taking it off. I will also inspect the t-stat area, but I don't think I have any questions on that.

[99yam40]

if you find the passages at stat and outer cover need cleaning the head needs to come off to clean them also

new gaskets for all

[DennisG01]

This is where I'm getting a little confused. If I take the head cover and head cover gasket off, wouldn't I be able to see into/through the head's water passageways? Meaning, doesn't the head gasket simply seal the head from letting water escape outwards and also seal the cylinder area? But I would still be able to see the head's water passageways without removing the head? Maybe I'm missing something or not understanding it correctly, though?

[99yam40]

yep you are not understanding the need to pull the head, there are passages around the cylinders that need cleaning.

But then I have no idea what motor we are discussing

[TownsendsFJR1300]

There's a HEAD, part #1 (bolts to the block) and a head cover, part #5 (bolts to the head).

Water runs thru both but to access the block (where most salt corrosion WILL be, the HEAD needs to come off:


2000 SX250TXRY Yamaha Outboard CYLINDER CRANKCASE 2 Diagram and Parts


.

[pstephens46]

Dennis if you get a chance....

Send some pics of this modified boat of yours. What did you do with all that engine space no longer needed?

[99yam40]

large fish boxes or contraband hiding places

it would affect center of gravity for the boat

[robert graham]

If you're not having an overheating problem why pull the heads and risk broken bolts?....Maybe just run some Salt-Away or similar deposit removal chemicals through the motor and save potential trouble with broken bolts?....

[TownsendsFJR1300]

If you're not having an overheating problem why pull the heads and risk broken bolts?....Maybe just run some Salt-Away or similar deposit removal chemicals through the motor and save potential trouble with broken bolts?....

Agreed 100% but the Salt Away, won't clean out the passages. I'd do the Rydlem or citrus treatment.

[DennisG01]

Water runs thru both but to access the block (where most salt corrosion WILL be, the HEAD needs to come off:

OK, that's what I wasn't quite getting. I was thinking that the passages through the head were a straight shot from the block - so that by looking from the head cover side of the head, I'd be able to see straight through to the block.

I like the idea of running a cleaning agent through and was originally thinking of Salt Away, too. But maybe the Rydlyme would be a better product for this application. I had always thought that Salt Away was more of a preventative type product that's best used after each outing, not so much for a "once a year" type thing.

So... If I remove the t-stats and take a look around that area... is the condition of the t-stat area relatively indicative of the rest of the block? What I'm thinking of doing is removing the t-stats, taking a few pictures, then reinstall stat covers WITHOUT the stats. Then, using a big bucket that fits around the lower unit, use a cheapie bilge pump and hook it up to the remote engine flush attachment and circulate the solution for a few hours. Then take "after" pics.

For what it's worth, I have no overheating or running problems right now. Just want to be proactive.

[DennisG01]

I will post a few pics of the engine-less area. Just have to figure out a new way to do it since photobucket apparently no longer works.

The boat handles fantastic - no issues at all. I store a few small things on the outboard side of the stringers in the bilge, not a whole lot, though. Maybe contraband would a more lucrative use of the space.

[TownsendsFJR1300]

Dennis, this site is really good, easy, no ads, free:

https://postimages.org/signup

Yes, pulling the thermostat or PRV will give you a good idea.

This is a pic of my F150 PRV, 10 years old(didn't leak but I did replace the seal(cleaned up the rest-the block was NO where's near as bad-guess salt water tends to sit in there), ALWAYS flushed/run-flushed:



I haven't done it but I would do the Rydlem or citrus flush as you described.
Pic's on those threads showed major improvement.

I recently started using Salt Away at the end of my flush. However it will NOT remove salt deposits already cooked to the block..

Now my lower unit (no engine heat):

[99yam40]

I think I would would drop the lower and hook a hose up to the pipe heading up to the power head like in the threads and use a pump as they used. that way it is circulating as the pump would normally.
but that is just me

[TownsendsFJR1300]

I think I would would drop the lower and hook a hose up to the pipe heading up to the power head like in the threads and use a pump as they used. that way it is circulating as the pump would normally.
but that is just me

Either would work, if you have a large enough pan to catch the cleaning fluid.

You don't have to yank the lower unit and as seen with that other 9.9 with ALL that nasty corrosion in the LU, (sailboat), it'd help clean that too..

Also, as large as Dennis' engine is, he may have to tape off some water exits, to try and keep the power-head full. He'd need a decent pump (very good volume).

And of course, pull the thermostat's.

[99yam40]

not much flow thru the pump using the power head flusher, but it may have some trickle back down