Proper flushing technique mystery

[garyN]

OK, here is the puzzle, please help me understand.

On my sailboat 9.9, 2002 exl shaft 4 stroke yamaha, I
use muffs after every run. Here is what I do -

Shut motor down, install muffs, turn on hose (low) start engine, allow it to get warm, disconnect gas line, allow engine to use all fuel, tilt up, remove muffs and then hose off the exterior of the entire lower unit, put canvas cover on power head and leave tilted up, completely out of the water.

My local Yamaha dealer had to remove the "exhaust cowling" and told me "it looks like it was never flushed EVER" "worst salt conditions we have ever seen".

Now my questions, 1. is it possible that salt water is entering this engine in some place other than the water intake ports that are just under the anti-cavitaion plates?
2. How would flushing the system ever flush out the inside of the lower housing? As I understand the cooling system, it is closed and the water that is picked up on the input, pumps up to the head and then out the "pee" hole. I always have a strong stream and actually check twice with the muffs on to be sure the water was not salt (yes I tasted it), I did that to be sure the muff seal was not allowing bay water in, because it can only be flushed in the down position. It was fresh.

Certainly, in the future I may switch to a bucket, but I always believed that muffs were good.

I don't have the built in flush port on the engine, and actually was told thet were inferior to muffs because they don't flush as well as muffs because you don't run the engine while using them - so the head does not get flushed as well as running it warm with muffs?

Don't know what I am missing here - but to me - if you take the lower cowling off and see packed salt, that is an area that cannot really be flushed?

** So, having thought about this more after I posted, here is the most clear way I can state my question:

If the exhaust system has failed, and no exhaust is coming through the prop at all, would water (salt) enter into the housing when the engine is being run (in salt water) with the fresh water muffs on? This is the only way I can explain how the engine appear to have never been flushed, when in fact it was flushed after every use? My thinking is that somehow, as the engine ran on the freshwater in the cooling system, that the outside salt water must have been being allowed in, through the inoperable prop exhaust openings? Any and all thoughts would be appreciated.



Thanks

 

[granpafish]

Re: Proper flushing technique mystery

I'm certainly no expert and I'm not sure that I understand exactly what is or is not going on. On most engines there is a flow of water along with the exhaust where ever that exhaust may be. Are you saying that there is no evidence of exhaust? Or is there exhaust without any cooling water? It would seem to me that if you flush after every use you are ahead of 50% of boaters. What ever the problem is, it is not your flushing habits.

 

[garyN]

Re: Proper flushing technique puzzle

Re: Proper flushing technique puzzle

Sorry

This question really goes along with the previous post under 9.9 power thrust problems continue. Om my 2001 9.9 poser thrust 25in shart four stroke, electric start.

What happened is, the exhaust tube the connects from the head and directs the exhaust down and out the prop failed (most likely a gasket i am told) . It failed up high in the engine and the "leak" burned a hole through the external exhaust cowling (about 5 inches below the engine cover. Because both the internal exhaust failed and the outer aluminum exhaust housing also failed, all exhaust simply comes straight out of the engine (straignt pipes anyone). No exhaust comes through the prop - unless you plug this hole! If you plug the hole it works like it is supposed to and bubbles in neutral - etc.

Now I think, because of the way the gasket failed, it actully is syphoning salt water UP into the engine from the prop (as the exhaust exits at the "hole" it is causing the lower tube to act like a straw - and bringing water up from the prop and into the cowling, then it just dries there. .

Really strange and it did a whole lot of damage - the replacement parts alone add up to $1,000.00 and the labor to take it apart and put it back togeather is estimate at 6-7 hours, so I am looking at $1,400.00+ in repairs, without the cost of the anual service ($200.00 I paid already).

Really starnge, but, in fairness to Yamaha they are acknolwedging the problem and are considering picking up the parts. This is fantastic for an engine that has been out of warranty since 2005!, so good for them.

I guess the only way to elimiate the flushing puzzle is to buy a "flushing bag" and be sure it only has fresh water in it (if I put it on while the motor is tilted up, then I can fill it, after I put it down and only Fresh water will be around the engine! Seems like a hassle - but at the risk of losing more hard earned $$, I may have to.

 

[granpafish]

Re: Proper flushing technique mystery

I went back and read the original thread and now I understand. Very strange. I've never heard of this kind of thing before. It almost has to be an assembly mistake by Yamaha or a faulty part somewhere. If you can put your finger over the hole, the gases can't be too hot. It sounds as if you have decided on repairing with Yams help. It would seem to me that the "salting" problem will be solved with the repairs.
When I first read your post, I was thinking that the boat was out of the water. I now realize that it isn't. What caught my eye was that you tilted up and that was that. If your lower unit wasn't getting the fresh water flush, that is bad. If your lower unit wasn't getting fresh water and then being tilted up, you were creating a salt water reservoir and that is worse. I realize that you had no choice other than removing the motor from the boat to flush but it explains the salting problem. As an extra precaution, you ought to get a jug of "saltaway" and the attachment for flushing. Not real expensive and seems to be a legit way to fight the salt.
I'd be interested in hearing exactly what caused the exhaust to burn (or rust) a hole in your cowling. Good luck, Granpa

 

[garyN]

Re: Proper flushing technique mystery

Hi

I will update once I see the actual parts that are being replaced. And I guess it is more accurate to say the hole was caused by "corrosion" and not technically "burned".

Some time in the next two weeks I am promise the engine returned. I cannot say anything bad about my experience with Yamaha Customer Service (this time) and feel quite impressed that they are willing to do the right thing on this.

Frankly, if Yamaha were not supplying the parts the engine would be simply "scrap" and that would be a true shame on a 2001 model that cost $3,2000 new. Actually the economics of owning this engine have not been that great. On top of the purchase price I have paid out $600.00 for service (carb cleanings (X4), water pump, and that does not include the cost I will pay for the service related to removing and installing these failed parts (I estimate $700.00)

Not exactly what I expected when I bought this engine. On top of that the engine has been out of service for over 18 weeks during the 60 months I have owned it. But most bothersome of all is that I have had to take it on and off the transome almost 20 time (and that is a real pain for this 111 pound beast.

Anyhow, many of us need to flush on the transom and I will futher explore this Muff in salt water issue. The only way you can flush a 4 stroke engine in in the fully down position (the oil and all) so, it has to be in salt water on the muffs. It is impossible to imagine lifting this off the boat after every use - that could be 5 times a week and my back simply cannot take that.

 

[Dakota Dave]

Re: Proper flushing technique mystery

We don't see alot of sail boats around here. but when I lived in Michigan the sail boats there had jackplates that lifted the aux out oof the water when not in use. they were fairly simple just put the lever in and pull it up.