OX66 frustrating issue

[TownsendsFJR1300]

On my F150, on the muff's, I don't have any issues getting the engine to warm up, thermostat open (rpm's drop to 700, ONLY when to temp).

1st Link, Flushing F150 Video by SRT-60 | Photobucket

I don't know what else your trying to accomplish besides a full flush, also thru the thermostat, etc.

May I ask what in addition to the above, are you trying to achieve?

[cpostis]

Again, matter of opinion. I believe that with no back pressure from an immersed lower unit, the block and heads will not be completely filled up with cooling water when flushed with muffs. Its would be like a car with a gaping hole in the lower radiator hose. There are two exhaust ports at the rear of my motor just below the exhaust guide. When in a tank flushing, water shoots a good 6' out of these ports. I also check with an infrared thermometer head temperature at each plug and on each side of the thermostats. I check for proper idle speed with the back pressure.
When flushed with muffs, there is barley any water stream out these ports. Now, what I will do when time allows will remove the two pipe plugs on top of the block and compare/confirm flow rate at the top of the block. I don't know if an F150 four stroke like yours is plumbed like my SX 150 two stroke. Here is an image of the pipe plugs and ports at the top of the block. The plugs are removed and sitting on top of the exhaust cover and the ports are the larger ones just below the heads in the image. I also attached an image of what deposits were internally in my motor before teardown.
Now, this motor has been in service for over 14 years, ran strictly in salt water. Never had problems once I got through my initial issues when bought in 2010. I expect I can get another five years out of her. However, I am prepared to go four stroke with a new Yammy next year. I take it you like your F150, any issues you care to disclose for my information? Thanks!!

[TownsendsFJR1300]

We had the same salt water build up on my neighbors 2 stroke 200 yammy. Once in a great while, he would flush it (not with muffs), the PO, probably not.

We ended up pulling both heads and scraping clean all the salt. The lower passages of the block were 95% blocked and would set off and go into safe mode over about 4,200 RPM's. How it ran that good, dunno... Once all the salt was cleaned out, ran great, no overheat alarms.

We're down stream of the Okeechobee lake so the water is usually brackish till you get into the gulf of Mexico(depending on how much "fresh" water their dumping)..

My old Evinrude V6 150, I regularly flushed with muffs, no issues. Once Evinrude made the attachment to power-head (for no running flush), within a year, my thermostat corroded closed. There's no doubt to me, just that flushing port is NOT enough.

From my experience, the 2 stroke on muffs will idle much higher W/O the back pressure (seems much more sensitive).

Now my inline, 4 cylinder, 4 stroke F150, on muffs or in the water, when cold will idle about 8-900 RPM's(especially during winter-water temp low 60's) for several minutes and the idle will not drop to 700 until its warm.

Winter time it DOES take longer for the RPMs to drop. The effect of back pressure on my 4 stroke is about negligible (as you see from my video)..

The thermostat, pressure relief valve, etc is ALL ORIGINAL (low hours on engine)..

I too am also very anal on flushing the engine with both the powerhead port, then on muffs. On the muffs, I'll give a rev every once in a while, real short to 2K RPM's so water hopefully makes it everywhere. PSI at the dock is about 55.

I'm a die hard 2 stroke, carb guy but was really pushed to the F150 by the sales guy.

The F150 is a bit heavier, fuel mileage is MAYBE 1/3 (closer to 1/4) of the 2 stroke. Maybe 2 MPH slower overall. Out of the hole, once propped correctly is pretty darn close to the two stroke and will easily pull a skier.

Oil changes are an additional expense BUT if you use the boat often, you'll save that in fuel easily.

The balancer was replaced under warranty (didn't blow but Yamaha wanted it replaced to prevent future failures)

The F150 is notorious for having a low idle and stalling when docking even new(which I also experienced.). There's a new method to fix /adjust it.

Back then, I had to find a master mechanic who was able to fix it (couple years ago) and it's dead nuts on still...


Even thou I've had NO problems with corrosion, I did just start using Salt Away as its cheap enough to protect my investment.

[scofflaw]

What say thee about the hundreds of thousands of boats that are on a mooring all season without a drop of fresh water to flush with ? And YES they do run just fine.


Bottom line.... flushing is over rated

[boscoe99]

Flushing is like insurance.

Might be never needed. But it is a small price to pay for what ever protection it affords.

For those that never need to file an insurance claim insurance it is way over rated. And a waste of money.

[TownsendsFJR1300]

What say thee about the hundreds of thousands of boats that are on a mooring all season without a drop of fresh water to flush with ? And YES they do run just fine.


Bottom line.... flushing is over rated

If your going to keep an OB engine for any length of time and its used in salt water you are definitely shortening its life.

You can look at many pic's here, where a block has major corrosion in it.

If you've ever pulled a head (engine over heating)and literally scraped for hours, built up SALT, I think you'd have a different opinion... An $800 fix at the dealer.

Its your boat/engine and of course do as you wish.

The pic's I posted above are of a TEN YEAR OLD ENGINE.


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From a Yamaha You Tube video:

https://www.youtube.com/watch?v=ZJaTjMOEKP0

"Published on Jun 19, 2013
Fresh water flushing is the single most important maintenance procedure a boater can perform to prevent corrosion in an outboard motor. Your outboard should be flushed after every use in salt or dirty water and this video explains how to perform the three methods of flushing an outboard: using a flush bag, flush muffs or the freshwater flushing attachment built into the outboard."


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