225 OX66 Service issues with local Grady dealer in Ohio

[family affair]

Some of you might have seen some posts on our '99 225 issues. We have resolved stalling, rough running, but have yet to crack high rpm surging and running rich. There is only one 5 star yamaha tech near our home in Ohio, but it is still an hour drive each way. This also happens to be the new Grady dealer that took over for another marina. I had contacted the service manager and requested a date to bring the boat in. The best they could do was 3 weeks out. Because it is late in the season and the dealer is not on the water, I had concerns about them resolving the high RPM surging. To avoid making multiple trips for issues that might not be completely resolved, I had asked the service manager (SM) to have a tech call me to discuss "the game plan". I told the SM I didn't have the equipment to do the testing required to track down this issue, so all I wanted to do was discuss what I was running into, and to understand the course of action that would be taken. After 1.5 weeks and 2 requests, I have gotten no calls.

I suspect the SM thinks I'm trying to milk the tech for info when in fact I'm trying to avoid wasting time and avoid a mechanic that doesn't know what the he!! he's doing. Too often I have had issues on vehicles that I could not track down without blindly replacing parts. I then decide to take the vehicle into an "expert" to only have them do the same thing I would have done, but charge me 3 times more!

Any advice?

Thanks

 

[GulfSea]

I work in a technical field. Hopefully you've kept a detailed log of exactly what has been done each step of the way to help figure out the problem. We've had issues run for months with skilled guys having a rough time finding causes. I've been on jobs where we've run a gauntlet of efforts to isolate a problem to have it suddenly resolve and we could not tell you exactly what repaired the fault.

So you're looking at 2 issues. 1 will be how well work to date has been recorded so it isn't replicated. 2 is the skill level of the guy this Marina has working. I know he's showing a 5 star rating but that doesn't always mean he/she's the best for this particular work. From a mechanical standpoint, if you called and demanded too much from me, I would lose interest in working on the motor. There's very little chance that we could come up with much with a phone call; difficult mechanical problems just do not typically work out that way. And I would be spending unpaid time in the process providing my hard earned expertise. But I absolutely do understand your position.

We recently had a problem where a valve had been changed twice. But the manual kept taking us back to that area of the system. There were probably a dozen possibilities and multiple valves that could have caused the fault. So we changed this one valve one...last...time and BINGO. The "two" previous valves were bad out of stock. It happens.

 

[family affair]

I'm not trying to get him to tell me how to fix the issue. I want to know:
1) I'm going to do "X" to determine if you have sufficient fuel flow.
2) I'm going to do "X" to determine if your thermostats are letting the engine get hot enough.
3) I'm going to do "X" to determine if your O2 is bad.

These are just examples of things that need to be checked to narrow down the culprit. All of which require special tools and knowledge to diagnose properly without tearing down every part and or simply replacing the part without probable cause. I don't want to hear "I'm going to hook it up to the computer to see what its says, etc." Diagnostic tools are only as good as the person using them. If he doesn't know how to troubleshoot, I might as well call iboats and start ordering parts myself!

 

[Pay2Play]

Can't help you on this issue but have seen posts on thehulltruth , there have been quite a few threads on this subject. I am a tech in another field and can understand your frustration. I also would like to know if you find a qualified tech in Ohio for future reference. Nothing like wanting something fixed and getting nowhere.

 

[GulfSea]

I'm not trying to get him to tell me how to fix the issue. I want to know:
1) I'm going to do "X" to determine if you have sufficient fuel flow.
2) I'm going to do "X" to determine if your thermostats are letting the engine get hot enough.
3) I'm going to do "X" to determine if your O2 is bad.

These are just examples of things that need to be checked to narrow down the culprit. All of which require special tools and knowledge to diagnose properly without tearing down every part and or simply replacing the part without probable cause. I don't want to hear "I'm going to hook it up to the computer to see what its says, etc." Diagnostic tools are only as good as the person using them. If he doesn't know how to troubleshoot, I might as well call iboats and start ordering parts myself!

Ok.

 

[jonjac90]

I have several comments and recommendations. Your post doesn’t state what steps you took to resolve the stalling and rough running. With that aside let’s start.

1. Do you have a fuel/water separator installed? Let’s assume – YES.
2. Have you attempted to verify if your gas tank may have a large quantity of water inside it?
3. How old is the fuel in the tank?
4. When is the last time you ran the tank down low, and attempted to siphon any water out of the tank?

I assume the boat is under load when you are experiencing “cracking” at high rpms, and the engine is asking for more fuel causing it to run rich.

Again have you checked your fuel/water separator?

I temporarily installed a “clear” fuel/water separator before the one that was already installed on my boat because it was a canister type and you couldn’t “see” the water being separated from the fuel.

When under load the “water” in the tank moved around causing the engine to run fine at one moment, until the fuel/water separator loaded up with too much water and the engine would reduce down until it received sufficient fuel back to it. This was causing the engine to run rich.

It was like someone was jerking the throttle back and forth, but the culprit was the aluminum tank was sweating and the water continued to build up inside it.

The first mechanic wanted to install new fuel injectors stating the screens are probably clogged. I check one of them and it was clean. It was a friend of a friend that said with the newer gasoline being used today, water vapor is the culprit if the engine was mechanical fine in the other areas.

Hope this comment helps, and maybe you can perform this test yourself with a friend right at dockside.

John

 

[grady33]

I agree with the fuel issue. I actually still use non ethanol fuel and top off tanks after every time offshore. Just winterized the boat 2 weeks ago and tanks are full with stbl added. Not sure how old the low pressure pumps are but I'd check hose along with the vst filters. I have also heard that these engines can eat up plugs although I haven't had a problem. While at it, clean the 02 sensor and make sure your oil pumps are working Ok. Just a few suggestions. Good luck.

 

[bayrat]

"When under load the “water” in the tank moved around causing the engine to run fine at one moment, until the fuel/water separator loaded up with too much water and the engine would reduce down until it received sufficient fuel back to it. This was causing the engine to run rich."

Having a problem understanding how a full water separator causes an engine to run rich. A full water separator causes a bypass and water enters the engine. When the separator is full, its full...from that point on what happens in the tank is irrelevant (i.e water moving around) Please explain what I'm missing?

 

[family affair]

The surging only happens over 4200 rpm's.

The water separator has been changed and there has been zero water in the engine mounted separator. Fuel has been ran almost completely out and topped off with new. Bad fuel doesn't make an engine run rich.
All filters have been changed and the anti-siphon valve has been removed. VST has been cleaned.

Rough running and stalling at idle was fixed with replacing LP fuel pumps.
Mid range rough running was corrected w/ TPS adjustment.

After pulling the plugs and seeing how wet they were and pulling the O2 sensor to find it covered with goo, I came up with this. The engine has had very little time put on it, which means it has had some nasty old gas sitting and ran through it. If the engine has never been decarboned and the O2 sensor has never been cleaned, the sensor might be too dirty to function properly or is bad. I plan to decarbon, clean the O2, change plugs and maybe have the injectors cleaned.

 

[jonjac90]

Sounds like a plan. You must trace all gas / air lines and verify condition. Pin holes or unseen cracks in these lines may be the cultrip.
You mentioned low hours on the end. For the season ending right now, how many hours did you run this season?
You stated at the 4200 rpm is where you are experiencing the issues. My comments stated above may be the cause. You are running the engine close to the high end of its range. All the systems have to be in great working order at this end of the range.

Are you performing these repairs or hiring a certified mechanic as mention on your previous post.

Keep us posted.

I'm curous what the cause turns out to be.

John

 

[Tucker]

Why don't you just buy the shop manual and test harness' required to test the unknowns?? I just bought a test harness for my TPS for about $40 from SIMS. You're describing classic symptoms of a bad O2 sensor; but it could fuel related. These Yami's are a little weird and you need a DVA adapter for your multimeter to read the peak voltage; about another $40. Can't think of a single instance where any tech will either confirm or deny if you've done anything correct. They perform a service and want to get paid for it, no free advice. Or, get educated buy the correct testing equipment and service your motors yourself. The money you save will pay for the tools. These engines aren't that complicated.

 

[family affair]

Tuck,
I'm not trying to get free advice from the guy, I'm trying to save myself from having to drag this boat several hours several times... not to mention wasting money. I can't tell you how many times I've been stumped on cars and taken them to the "pros" only to have them replace good parts and not correct the issue.
The fundamentals of the engine are simple, but when you are tracking down a symptom with several potential causes, clearly identifying the problem can get a little tricky IMO, especially when it is possibly I could have more than one issue at a time.

Coincidentally I just got the part numbers for the O2 and TPS harnesses today from SIMs. I'm ordering them tonight.

I checked the O2 using the torch method before cleaning it and the voltage change was slow. After decarbing the engine and cleaning the O2, it seems to be normal. The plugs seem to be more dry too, but still not where I think they should be. I think to do a better job of decarbing, I need to be on the water to get all 6 cylinders firing.

Once i have the harnesses, I will check the O2 and TPS again with the engine running to see what I get.

 

[Tucker]

Might want to poke in on the Yamaha forum at boats.net. Search members list rodbolt13. The guy is a master tech but stop posting all of the sudden about 2-months ago. Lots of posts and you may see something. You can bet you're not the only one to live that problem. Feel your pain and have been bit many times by techs that sometime seem to know less than me. I think you got a simple problem and it's manifesting itself in different ways. Most of the problems with our OX66's always fall back to a fuel system problem. Looks like you covered that pretty well, though. Sorry you're having the problem, please keep us current with developments

 

[family affair]

Tucker,

Have you ever checked your TPS voltage per the shop manual? Here is what I got:

I ran the TPS functional test per my book. Engine off, ignition on. Throttle closed the tps gave me ~.63 volts. WOT it made only 3.96. According to the book, the range is .48-5.25 volts. Is my TPS bad on the top end?
Btw, I adjusted the TPS before I started per the book procedure and got it to read .50 volts. It initially only read .39 volts. The correct range with the throttle plates closed is .48-.52 volts.

Thanks

 

[Tucker]

Family affair, did you use a DVA adapter with your multimeter? It is required when testing the Yamis to read peak voltage.

 

[family affair]

What's a DVA? You mean a DVOM - digital volt ohm meter?

I used the Yamaha test harness and my DVOM. My tongue isn't calibrated to read that voltage... yet! :mrgreen:

 

[Tucker]

The DVA adapter allows the meter to read peak voltage.

 

[family affair]

No I did not use a DVA. My service manual had no mention of it.

Also Andy at SIMS thought my results were typical. I think it was out of adjustment, but not bad.