225 OX66 - draining water from bad fuel

[goose70]

On another thread I posted about how my motor had "bogging" problems at high RPMs and I appreciate the responses.<br /><br />After checking the VST filter, cleaning the O2 sesnor, etc., my mechanic concluded that I still have some water in my fuel and that water is the cause of the bogging problem. He drained the water from the motor and fuel/water seperator and it then worked fine for about 15 minutes at 4800 RPM. But then it began losing power again when I ran it for about 1 hour yesterday.<br /><br />Prior to running it, yesterday, I installed a RACOR B32013 fuel/water seperator with a clear plastic bowl through which I could see any water that had accumulated in the fuel. I ended up draining about 2 oz of water from it after the first hour, yesterday. Nevertheless, the motor continued to lose power, which was especially noticeable above 3000 RPM.<br /><br />My questions are: <br /><br />(1) shouldn't the fuel/water seperator be catching all of the water before it gets to the engine. I thought that RACOR was particularly good at this?; and<br /><br />(2) Can a novice like me easily drain any water that gets into the engine? If that's what's causing the bogging, draining the water seems like an easy sollution.<br /><br />Thanks again!

 

[rodbolt]

Re: 225 OX66 - draining water from bad fuel

yes you can. the brass slotted plug on the VST is a drain. remove it and catch the fuel coming out in a clean container and inspect it. if thats not the cause your going to have to get a bit deeper.

 

[goose70]

Re: 225 OX66 - draining water from bad fuel

After draining and examining the gas in the motor, it turns out that the water in the gas is no longer the problem. The new Raycor filter is getting it all.<br /><br />So now I'm back to square one. Even though the mechanic said the VST filter looks clean, I'm asking him just to replace it (I'm worried that it may have water in it, so look clean while actually impeding fuel flow at high RPM). I'm also asking him to look at the low pressure pumps and replace if necessary. Am I missing anything? He cleaned the O2 sensor a couple of weeks ago, so I can't think of any other likely cause.<br /><br />Thanks, yet again, and I'll continue to keep you posted.

 

[fondafj]

Re: 225 OX66 - draining water from bad fuel

goose70, <br /> Run the engine with 2 diagnostic guages attached and monitor during the loss of power. Use a vacuum guage on the fuel line just as it comes inside the cowling and use a pressure guage on the high pressure fuel line. If there is a fuel line restriction or a tank pickup problem, the vacuum guage will show it. If the VST filter or low pressure fuel pumps are causing the problem, it will show up in the high pressure guage....<br />But,<br /> - Low pressure fuel pumps are a known fail item - if you can not confirm they have been replaced, they are cheap enough, replace them anyway.<br />- Spark plug resistor ends do fail often... of my 12 (2 outboards), 6 were bad. Easy to check ( 5 min per plug) cheap to replace.<br />- VST filter - sounds like this filter has seen water a bunch of times - it may not help but I would change it just because.<br />I'm sure rodbolt or BenC can add more-

 

[rodbolt]

Re: 225 OX66 - draining water from bad fuel

any updates ?

 

[goose70]

Re: 225 OX66 - draining water from bad fuel

Here's the update: The mechanic came out last evening, replaced the three low pressure pumps and the VST filter (all covered by insurance, since I had no problems before getting that one batch of bad fuel). We then test ran it and still encountered the folllowing issues:<br /><br />(1) Although much improved from before, the boat still did not hold its RPM consistently. I opened it to 5200 RPM (full throttle) and it ran wonderfully for 30 seconds or so, then bogged down to 49/4800, occassionally jumping back to 5200 for a few seconds. At lower RPMS, it bogged, but less severely (for example, at 4500, it bogged down to 4400 for a minute, then to 4300 but stayed there for the next several minutes. Some RPM zones seem to be more tmepermental than others. At 1500, it surged beteen 1700 and 1300. At 4100, it seemed fine.) My mechanic tried manually pumping the fuel ball at high RPM to see if the problem was with vaccuum pressure in the hose, but it made no difference.<br /><br />(2) My mechanic noticed a tapping noise below about 2000 RPM, which he thinks is from one of the pistons. Above that, it seems to go away. I can't recall what he thought that was, but he was happy it went away at high RPMs.<br /><br />Unfortunately, we are now both at a loss as to what to do next. He suggested I change the plugs (about 130 hours on each) and put fuel injector cleaner in, figuring that the water/bad gass may have exaserbated a problem in those areas. Although he cleaned the O2 sensor, he speculated that perhaps a little of residual water may have made its way to it since then, which might also cause the problem.<br /><br />In any event, he said that if I can live with how it's performaing now, it may be better to wait until winter when he can take time to fool around with it at the shop.<br /><br />Any of your thoughts would be appreciated, since I am running out of patience end with this motor.<br /><br />Thanks!

 

[goose70]

Re: 225 OX66 - draining water from bad fuel

One other thing....I don't know how much of a difference this makes, but of the 130 hours on the motor this year, about 50-60 of those are tolling between 500-800 RPM. Could I have gummed something up from all of this trolling?

 

[rodbolt]

Re: 225 OX66 - draining water from bad fuel

centsless bout coverd all the quick easy bases. test compression before starting and go for the maint.

 

[goose70]

Re: 225 OX66 - draining water from bad fuel

OK, I replaced all six plugs, took her out for a test and, while noticeably improved from when I first posted, it still bogs by 300 RPM or so at higher RPMS and between 1300-1700, plus it is rough at low speed and a little smokey. I'm thinking that the only culprit left is the O2 sensor. My mechanic cleaned it at the boat a few weeks ago (using the approved solvents) but that didn't make a difference, so I'm worried that it's shot.<br /><br />One other notceable item is a tapping noise comming from the engine below 2000 RPM, which is still ongoing.<br /><br />Am I going from bad to worse? Is the investment in a new O2 sensor worth it at this point?<br /><br />I feel like my motor has been placed on this earth to test your knowledge of everything that can go wrong.

 

[fondafj]

Re: 225 OX66 - draining water from bad fuel

Originally posted by Centsless:<br /> goose70, <br /> - Spark plug resistor ends do fail often... of my 12 (2 outboards), 6 were bad. Easy to check ( 5 min per plug) cheap to replace.<br />

-Check these yet? They unscrew from the high voltage cable and are easily tested with a multi meter. The expected range is around 5K ohms. Replacements are around 10 bucks @. <br />- Test the O2 sensor before replacing. Do a search here and you will find a wealth of info on testing. Also: http://www.boatsetup.com/O2sensor.pdf <br />- As rodolt indicated, a compression test is in order.<br />- The tapping may be the O2 sensor draw tube moving in the block cavity. If so, not really a problem.

 

[TomS]

Re: 225 OX66 - draining water from bad fuel

It might seem obvious, but make sure the mechanic is also inspecting/cleaning the O2 sensor draw tube, and not just the sensor itself. I had a similar tapping noise at lower RPMs and discovered that my draw tube was completely carboned up.. and this after my mechanic supposedly checked the 02 sensor a month or two before.<br /><br />-- Tom

 

[goose70]

Re: 225 OX66 - draining water from bad fuel

Here's the update on my OX66 issues:<br /><br />The new O2 sensor is on it. The compression is excellent on all cylinders. I checked all 6 resistor ends (all were between 4.8 and 5.0, except one that was 4.29, which I'm told is still ok). I also had a Yammie rep come out and give it a second look. <br /><br /><br />The motor runs very well now...much quieter at low RPMs and very little surging (except when at awkward load speeds while the motor tries to adjust...I'm told this is normal). The rep had my 4700lb Parker running at 41mph at 5600 RPM while testing her (and that was with trim tabs that are now covered in barnacles). The rep told me it runs like new.<br /><br />Except for one MAJOR item...that tapping noise. It's apparently a knee pin in the #4 cylinder. The rep told me that I will need a new powerhead, although he doesn't think it's getting ready to blow just yet. He said this was also likely caused by the water saturating the motor during the water-in-the-gas episode. If so, I'm hoping insurance covers this, too, as it has for everything else so far. After all the work and time lost, it's pretty devastating to learn of a $5K problem just as the motor seems to run well again.

 

[rodbolt]

Re: 225 OX66 - draining water from bad fuel

if he is positive its a wrist pin its a 1200 dollar fix if you do it now, if you wait till it braeks the powerhead is normally scrap. right now at worst you need i rod,gasket kit,wristpn,pin bearing and maybe a set of rings, possibly a piston, if it breaks odds are it will toss the pin through the block scapping the whole thing.<br /> what method was used to determine a loose pin? and if its loose its in immenent danger of self destruction. they wont run loose long at all.<br /> so why replace an entire powerhead over a wristpin ?

 

[goose70]

Re: 225 OX66 - draining water from bad fuel

This is very helpful. Thanks. My regular mechanic said the same thing (i.e.- I may not need to replace the powerhead at this point). I'll find out as soon as I haul the boat.