New update

[RussGW270]

Okay, so I may have bought myself some time, however the likelihood of the engine being viable in the long term, as far as improving it’s compression is looking less likely.

I have replaced the plugs, fuel lines, fuel separators, oil, lower ends serviced, fuel filters, etc...

I ran Mystery Oil both inside the cylinder as well as inside the oil.

I hot shot Seafoam into the Fuel Separators and also treated the aux tank with 2oz per gallon, and the main tank with 2x per gallon. I ran each engine for an hour, alternating between idle and 2700 rpm.

The compression did not improve.

That says to me that while there are no shavings etc in the oil, which was clean, it has a leak and will probablyrequire arebuild soon, since that onecylinder is right at 90psi.

Both engines run smooth and quiet, but I can hear a slight knocking on the one engine with the low psi....very faint, that tells me I “may” be able to rebuild the single cylinder,but more likely not.

So, they run fine for now, better than most that have no idea what their engines are doing, but making plans for what to do next.

I have a ridiculous quite for a top to bottom rebuild on both engines of like 18k bucks....will shop that around as I do not want to rebuild them, even if I can.

For now, may still take her to the coast and see how she does. They both ran amazingly well and quiet for an hour each, which surprised me so...who knows.

R

 

[seasick]

I didn't expect that the compression would improve with new filters an oil change. Did you measure the compression before and after shooting in some mystery oil? In that case, I might expect an increase in compression.
In any case, rings are probably stuck or broken. I don't like the fact that you hear a knock. Can you tell if it is a mechanical knock or a combustion knock (ping)?
Did you run the motors in gear? If so, did the knock change tones? Pull off the plug wire on the low cylinder and see if the knock gets better or stays the same.. I am not sure that the knock and low compression are related. They might be or the knock might be something unrelated.
Have a beer or two.

 

[RussGW270]

I will be doing more testing but the only way the compression would improve would be if there was actually something stuck. That being said, there is still a very slight chance it could improve, but I doubt it. Is the “knocking sound” related? Maybe not. Imo, does not matter.
At this point, what we can surmise is this - Most people have zero clue about the compression of their motors till the motor exhibits a more severe symptom. The fact I tested it even though I had no indicators simply means I found out early.

related to the cylinder or not, it needs to be repaired. Since the engine is about 160-165 psi on the other cylinders, it makes no difference if I repair one as the others will be so far off...the engine would probably run worse.

So, I baby the engines...I keep them running as smooth as possible for as long as I can. I keep the oil changed, check it often, keep it pampered and draw out the engines as long as I can and then, rebuild or replace them.

There is no quick fix for the engine, there is no partial fix. I either rebuild it all or replace it all. Since this is the newer engine and the other has like 1300 hours and 165 psi also, I can think about doing one and then the other the following year...a rebuild....might hurt less heh...but, this engine is, again....imo....pretty much done as far as repairs goes, unless I do a total rebuild.
No small answer for this one engine, best I can hope for is to drag it out and hope it hangs on as long as possible.

That being said...the knocking is very very faint....most would not have noticed it, but I am strange like that heh...so, could last a month, could last a few years..who knows.
R

 

[RussGW270]

Okay... good place to be. I just sent an email off to a guy in Granger that I spoke with last week. Scheduling time after the 1st so they can give her a full shake-down and test on both engines. I told him my GOAL is to figure out exactly where we stand.... condition of the engines and boat as a whole.. and then come up with a plan, if at all possible, to keep her going for as long as possible... and figure out rebuild vs re-power.

If one engine requires a fix.. no big deal. If it requires a rebuild.. well, then we do one engine.

As I thought about it.. if I get one engine rebuilt one year then the other the next... it "staggers them" and makes it more affordable... so.. eh.. glass is half full.. but, I think I have gone as far as I care to go with the repairs.. and she is in a place now where a professional mechanic needs to really dig into the issues and help formulate a plan.

Will let you all know how that comes out. I seriously do not think anything will be required...probably.. most definitely needed.. and I am thinking that, given the results of "my" tests, the "fix" needed will not be an entire rebuild. No other cylinder has an issue...so, I am thinking we will need to fix that... and that could buy us a year.. in which time I can more easily convince the wife of either total rebuild or total re-power.. lol.

Maybe freaking Suzuki will come out with a dadgum 225 that does not jump in weight by then


R

 

[wrxhoon]

Russ,
The knocking sound is a worry because if it's not related to the bad cylinder it could be a bearing knocking, if that's so it will eventually spin the big end , worse case put a rod through the block then it is new power head.
The idea of testing compression with some oil in the crook cylinder you may find out if it is a burned valve in that case you could just rebuild the cyl head. If comp increases with oil it's bad news, it means stuck or broken compression rings, more than likely overheated at some stage .
If you have a good engine there is no need to rebuilt it just do the crook engine . These engines if looked after they last 1000's of hours.

 

[RussGW270]

I get it... going to let them speculate and test vs me.

It may be my imagination as I have too much vested in this, so going to let them look at it without any bias or per-conceived ideas. This needs a professional mechanic to evaluate. I am fine maintaining, but I simply do not have the time or resources to dig into it too much... could I? Sure.. but would I want to? no... and it would be a lot more costly for me to do it halfway then say, "okay... all yours".. heh

So, they run well. I am going to do one more test, simply because I am curious, then turn it over to a proper mechanic to evaluate and give ma a forward action plan.

Oh, and WRX.. totally agree with you, btw.. and appreciate the input. I am simply stating that I think they can last too.. and the "knocking" I think I hear may be nothing, may be related, may be something else. At this point, these engines are running so smooth and easy, I have to assume I am not doing something correct and so will let a professional evaluate them.

My wife would be happy if I sold the boat... not going to let that happen, period. She will not let me rebuild them or re-power right now, end of story. I have put off a lot of other priorities to get this boat to where it is now, and to be fair.. she has priorities too so... my hope is to get a professional to evaluate and repair, if needed, so they last a year or two or whatever... at which time replacing or re powering will be fine. If that engine will not take a "repair" that is under $1000.... then the boat sits till next year, unless "I" decide to do the repair for less over time... no way around that. Not going to stress her out or tick her off. She has let me come this far.

So, will see what he says. If they can repair for under $1k, then we will be able to do that.. if not.. we will see what they say.

R

 

[RussGW270]

Duh... stupid me realized yesterday that I forgot to put the boat in neutral and test with full throttle.

As such, the correct numbers are as follows:

Engine #1 (2003 model)

All cylinders 205-210

Engine #2 (2004 model)

5 cylinders 205-210
2nd cylinder from the top, on STBD side - 125-130

So, there is at least that.. heh

Would explain why they are running so well, most numbers are where they should be.

Russ

 

[seasick]

Some may disagree but I believe that compression tests on modern motors should be done with the throttle plate in its normal idle position. Opening the throttle may skew the numbers to look better than they really are.Regardless, cylinder 3 is a problem. As mentioned, run the test on 3 again then add some oil, maybe a tablespoon into the plug hole and retest. Crank the motor as many times as it takes until the measurement stops changing.
I am interested in the readings. If the compression doesn't change significantly after adding the oil . Another test,, although it is a long shot,is to measure the valve clearances for cyl 3. If the clearances are way out of spec, it might help explain the compression loss.
Note that adjusting the clearances is not a simple job.

 

[RussGW270]

Clearly, idle vs full skews the numbers heh. I prefer to do it the way it is supposed to be done, and done by most other people, as it explains why that cylinder is firing. At 90psi, it should be mis-firing some... and it is not. So, more realistic.

Still an issue, like you said, but it gives me more perspective on why it did not show prior to this.

I meant to scope it last night, but was too hot too long heh, so will try to do it tonight. Cannot see anything in the daylight on the scope

As far as further tests, I may attempt looking further, as I wait til I can get it to the tech, but not going to fully disassemble anything as it would cost more for them to fix it I am sure

R

 

[glacierbaze]

Hard to oil the rings on a horizontal cylinder. I would bump that cylinder halfway up, and soak all around it with a squirt can, then spin it over a couple of times by hand to make sure you don't hydralock it, before I screwed the compression gauge in.
Or do it all with the engine tilted full up.

 

[RussGW270]

With all due respect heh... I have put every sort of cleaner and or oil and lubricant through this piston that was worth trying, tilted, horizontal, both ways. I have run it for about 2 hours, alternating the throtle all the while. I seriously do not think this is a question of something being stuck, it is an issue with a leak....most likely a bad seal or gasket. Cranking it by hand, at this point, is not going to resolve this issue, albeit on a first try, probably a good way to soak it.

R

 

[wspitler]

Run it like you stole it (In a lake, the Gulf or the Laguna Madre) for 50-100 hours. May get any carbon out. I'd try adding Techron to your gas also. Nothing to lose, it probably won't blow up without any warning signs!

 

[RussGW270]

Oh, I will.. heh... but plan to get it looked at by a pro. I also plan to run a leak down test tonight on it.. see if I can see where it is losing pressure. May not see anything, but eh.. nothing to lose.

R

 

[igblack87]

Get a couple Seven Marine 627's and throw them on the transom. No problem.

The Seven 627sv - Seven Marine - Seven Marine

Seven Marine is committed to providing world-class outboard power with its 557 and 627 outboard engines. Unmatched horsepower, unique geometries and patented technology.

www.seven-marine.com

 

[glacierbaze]

With all the stuff you have poured thru the cylinder, AFAIK, you still haven't reported any compression numbers with oil in the cylinder. That oil is not a lubricant, or to free up anything stuck, it is to fill the ring grooves, and see if the test numbers go up b/c of bad rings.

I have never owned a 4 stroke outboard, but doing a leak down test on cars and trucks 50 years ago, we always pulled the dipstick and listened to hear any air leaks there, from leaking rings. And, listened thru the valve covers for leaky valves. Marine dip stick tubes go all the way to the bottom of the oil pan, so that you can suck the oil out, so I am not sure if you can tilt the engine enough to hear an air leak there, I would drain the oil pan. I have no clue how a 4 stroke valve cover is designed.
Are you using a dual gauge leak down tester?

 

[wrxhoon]

[FONT=arial]seasick[/FONT],
Normally with age and wear valve clearances get bigger so adjusting them wouldn't help the valve sealing better . I never had a Yamaha 4 stroke apart but I'm guessing it will have bucket and sim like most modern twin can engines and like you said very difficult for a none pro to do them. He can easily do a wet compression test though, of course a leak-down test is much more comprehensive if he has the tool.
wspitler,
Carbon built up will increase compression ( not decrease) because the combustion chamber is somewhat smaller if there is carbon built up .
Russ,
If you have a scope use it you maybe able to see if the bore is scored, if it is scored then you know you have bottom end issues.

 

[seasick]

A few comments:
Putting oil in a cylinder can not cause hydraulic lock as long as the spark plug is out or the only thing attached is the compression tester. Just don't be looking into the hole when you turn over the motorThe idea of the oil is not to loosen things up or clean them, it is simply a method to get a better seal around the piston if rings are not working up to snuff.

You would have to have a lot of buildup on a piston to significantly change the compression. The comment that carbon buildup can not lower compression is not true. If the carbon gets in the ring grooves, it can cause sticking and often cracked of rings rings. Sticking is not good but cracking can lead to serious damage.

My comments about valve lash adjustments was suggested to see if clearance was low due perhaps to a bent valve or a valve with buildup that wasn't closing all the way.

An issue with a valve is a lot less of a repair than a bad piston or ring so to me it makes sense to see if there are indications that a valve may be an issue.

 

[RussGW270]

Guys, I appreciate the input.. but, @glacierbaze I am not new to this.. heh. I am not giving a "blow by blow" account, but I assure you...I have more experience working on engines than you know. I can attest, that while I am no expert, I have evaluated as much as possible without tearing the engine down. Can I do more? yes, but the likelihood of producing any significant change in results is low, without pulling the cylinder head. I have poured Mystery oil directly into the cylinder. It was not "Yamalube" but it has the same effect and is designed specifically for that purpose. So, I assure you... what is wrong with this engine is going to need that engine broken down at least to some degree to check it.

@seasick - Agreed, I want to scope it, but due to my work schedule and the fact money is tight the rest of this month, heh.. I have not gone further. I have a scope, but it is so hot and bright outside, I need to wait till after the sun goes down or I cannot see the screen of the scope... go figure. Due to working at 5-5:30 am each day, this has to wait till the weekend. I like your train of thought and am actually going that way, but the compression tester I had was junk.. the one I borroed has to go back this morning... so waiting for a new one in the mail.... everything is reliant upon money and time

I plan to scope it as well as I have a leak-down tester being assembled... I am waiting for a new compression tester adapter to use that. My goal/hope is that I may be able to see or hear the escape of air or fluids.

Look, keep giving input..guys.. I like it.. it keeps me thinking, but I feel people get worked up when I do not follow their input to the letter.

I only have so many hours and so much money per month to spend on this boat.

Another cool aspect of this, I think.. is how many folks are really into getting this boat on the water... lol. It is too bad you all cannot all fly down here and gather and have a Grady intervention

This month, my boat funds were eaten up by new water pumps, 3 new batteries, new breakers...and a few other odds and ends.. heh. Aug 1 means I get to buy a few more items.. so, we'll keep at it, however.. I have to set aside some of that to pay the nice guy in Granger to really take an experienced look at the engine and possibly fix it fully.

What is good is the fact that I caught my mistake and was able to pull real numbers. Honestly.. yes, the low cylinder is not good, but.. the numbers give me hope these engines have a lot of life left. If they are pushing 205-210 now, imagine when I am able to get that one cylinder repaired.. may add 5psi to the ones that are not hitting 210.. who knows...gotta keep a positive spin on it all, right?

Yes, I know.. there will be those that say "has nothing to do with this.. "....All I have is positive momentum, glass is half full....so offer ideas, but please .. don't rain on the parade here.. heh.. the parade is happening anyway

We will get this boat going, working top notch.. I say "we" as you all have a vested interest in this as well.. and I love that, I do.. I am trying to get it going just as fast as I can heh... and I pick and choose what tests I think offer value and can work. If there is something you want me to try, let me know. If I feel it is a valid test, I will do it. If not, I won't, simple as that. Not being mean, just do not want feelings hurt if I did not do something they asked me to do. Does not mean you or I am wrong, means we differ in our ideas of where to go... and since the boat is here.. well.. lol

Okay, gotta work. Will have more test results as soon as new parts arrive and money allows

R