Overheat question

[Redfred1]

I have a '79 Evinrude 100HP; Serial# 100999S. First time crank up this year; it finally started; ran it on "muffs" about 15-20 minutes while I cleaned out the other stuff out of the boat. Pee hole working OK; but did keep track of the temperature on the heads; block; etc. (Infrared gun). The port side is reading 160; the other side is 140. Overheat sensor did not go off.
This engine is used mainly in salt water; but gets a Good flush and washout after every trip. Have heard about the "Saltaway" but haven't used it. Will do that first; but should I look forward to pull the outer plate to clean out the ports?

Don' t know what normal temp should be. Any thoughts or suggestions

 

[racerone]

When was the impeller replaced last ?

 

[Redfred1]

Two years ago. Probably (guessing) less than 50 hrs..I have only had this unit that long ; and service was done by someone at good shop.
I have not done a compression test; all the plugs look the same; is running on year old gas.
Looked on the "Rude" outboard for some insight. Saw a comment about a dedicated flush port; probably not on mine

 

[oldboat1]

Impeller should still be OK. It's a big lower unit, but try idling in a big trashcan -- hose running, monitoring temps. 160F is too hot. See if the temps even out around 130-140 with the l.u. sunk deep (well over the water pump).

 

[Redfred1]

Will do Mr. boats. Going to town tomorrow; will look for that "Saltaway"; and give it a try. (Can't Hurt)

 

[Escambia]

Salt away is your friend! Little pricey but well worth it.

 

[F_R]

For the upteenth time, you cannot test a water pump by running on muffs. The pump isn't pumping when you are doing that, just allowing hose water to pass through. A big can is better but not much. You need to launch the boat and test it in the lake (or sea, in your case)

 

[oldboat1]

retired to fresh water (and snow), but had some prior experience with Saltaway. Think it’s a good product, although periodic fresh water flushing in a trash can (with or without the Saltaway) is a good idea, imo. Water will heat up, so keep the hose running and monitor temps.

I still pull out lures with rusted hooks — but remember some nice rockfish.

 

[Sea Rider]

You can flush an engine with fresh water aftyer boating on salt water for any time period, but all engines will start to internally collect salt layers one on top of the other on all water passages due to continuous ON/OFF variable temp cycles which in the long run will need to be mechanically scrapped out by pulling complete powerhead down.

Salt Away is an ideal product to maintain an engine running good while flushed regularly with it specially being new engines out of the box or used ones that have been through an exhaustive overhaul process,

On extremely salted water paths not sure how much salt layers, crust will be removed, no one will pull all powerhead gaskets to check that out LOL!!

No issue testing engine on muffs while geared if you want to as long muffs don't lose water pressure through ear sides so to provide full water amount at lower leg.

Happy Boating

 

[Fed]

Water dissolves salt really well and make sure your muffs are overflowing while flushing.
I think any white stuff left in your motor could be called corrosion.
Infrared guns can be a bit hit & miss. Google "emissivity".

 

[oldboat1]

Muffs (flushers) are often more convenient, so don't mean to rule them out. Just not good for troubleshooting.

About half pressure at the hose is good -- gives you the overflow mentioned above.

 

[Redfred1]

Thanks for all the comments! Have held off posting until I found a compression checker. All show 121-122. (I consider good for a OB this old; plus low compression or a crappy plug would show something too).
Can't find Saltaway close; can order it from WM; takes a week. Around 40 bucks.
Two infrared guns show 1dg. difference
My washout barrel is too big; guessing 2oz. of SA per; gallon of water; will get a 25-30 gallon tub.
Still might have to pull that back plate as Mr SR said; just a gasket and new stainless bolts.
More thoughts or suggestions welcome!!

 

[Redfred1]

Can give a good update! After almost 3hrs of running off and on; it started to cool down to a decent level.
Used a 30 gallon tub; 5 gallons on vinegar; let the hose keep the tub full; kept track of the temp; after about 45 minutes it started to drop. Both sides are around 122 at a medium idle. Let it sit for an hour; then let it run almost 30 minutes; no change. Will check it again tomorrow.
Found out a lot of things: # II gave is the Model#; this OB does NOT like year old gas (with Stabill); and washout tank over the "Muffs".
Thanks for all the help and advice!!