Does this steam look abnormal?

[ajgraz]

Re: Does this steam look abnormal?

Good deal on the temp reading, let us know.

Question, even though the pee-hole water was "steamy," was it hotter then you could stand to touch? Hose muffs sometimes blow / cavitate a lot of air bubbles into the water, and these can cause vaporization inside the water jackets even though the overall temperature might be OK. This is the main reason I'd like to see if it steams if run in a barrel of water instead of muffs.

Also really still want to know, seeing any evidence of moisture-fouling (as in water, not oil) on the plugs?

 

[Larson70]

Re: Does this steam look abnormal?

Just bought digital thermo, what should the temp of the water be coming out? It is on muffs. You can put your hand in the stream for 3 seconds without feeling like your hands burning.

 

[oldman570]

Re: Does this steam look abnormal?

The water temp should not be above 150 at the TT if everything is in good shape. You should be able to place your hand on the water exhaust cover and hold it there for quite awhile without getting burnt. I can hold my hand on my 70hp 1987 for as long as I want and not have to worry about getting burnt. I have a 145 degree stat in mine. Have you checked the popit valve or rebuild it? It should be just below the stat. It could be that it is not openning as it should. JMO
Oldman570

 

[ajgraz]

Re: Does this steam look abnormal?

Seconded that temp should read not more than around 140?F at the pee hole. That's like really, really hot tap water.

You can put your hand in the stream for 3 seconds without feeling like your hands burning.

That's a good sign to me that your temps are probably OK after all.

 

[Larson70]

Re: Does this steam look abnormal?

the temperature is 137. It seems to pee with a mix of exhaust or steam out the tell tale hole...It has a steady stream at all times unless you bring it off of plane too quickly then it stops peeing and converts to pure steam or exhaust gas or both. In order to get it peeing again you have to turn the motor off and start it back up. It did not overheat or stall while we were on the water for 2 hours today. We just had to gradually decrease throttle to keep the water flowing. What do we think?

 

[Maxz695]

Re: Does this steam look abnormal?

Hard to say I,m thinking here, and could only come up with something in the midsection or adapter plate creating blockage when backpressure is made while throttling down. This could be from a bad groment on the base plate for the water tube. A corroded water tube. Worn impellor. Cracked housing. Particals from a blown impellor dancing around creating an intermintant blockage in the adapter plate. I had this happen on my 40 HP. I found impellor parts trapped in th base as well as the exhaust port plate. as well as a corroded divider plate. Interesting thread might want to read through it http://forums.iboats.com/showthread.php?t=581185

 

[ajgraz]

Re: Does this steam look abnormal?

Larson70,

I am of the opinion that, unless you find water (or a "steam-cleaning" job") on one or more of your plugs you do not have a problem with your exhaust baffle or jacket. Last night I just finished up install of a 1988 60hp, freshwater-only (i.e., no corrosion), totally re-gasketed (by me) powerhead onto my salty old 1978 70hp Merc. Ran it in a barrel, timed it, and my pee-stream looks exactly like yours, very strong with a little bit of wispy steam. And my temp gauge read 135-140 F at all times. I'll try to get a vid if I get the chance.

Now as for what's causing your waterpump to effectively "lose prime," I dunno. When's the last time you changed the impeller? Did you look at the stainless steel "cup" insert in the water pump upper housing or the stainless bottom plate to see if either is scored? Or maybe your motor is mounted too high and the water intakes are sucking air when you're at (or coming off of) WOT?