Port Engine fouling plugs running rich

[gsnickle]

Okay, new to the site and jetboats, but have lots of experience with I/O and outboard engines. My "new" 2005 SX230 ran great on the test drive, and the first time I took it out. 2 hours of run time later the Port engine is running very rich and fouling out plugs (all 4 of them). Yesterday it would not idle or start without flipping it to half throttle once under way. I have plugged it into the computer and run an injector test with all 4 hitting 20 for 20 times. I have replaced plugs and coils, and checked throttle position (0.79v at idle). It has fouled out all 4 plugs within 2 hours of run time and has a really bad gas smell in the exhaust. I was hoping that it was not an ecu, but it is looking that way to me. Does anybody have any advice or history with a problem with this?

 

[dgfreeze]

Not a super quick test, but I'd be swapping ECU's to see if the problem stays or goes to the other engine.

 

[gsnickle]

As soon as I get the time, I will swap them. But, it looks like I need to hold nuts on one side of the firewall, and bolts on the other side. How does one do this alone?

 

[dgfreeze]

Lol, it’s a pain, I just did it a couple weeks ago. A vise grip on the nut works, but it’ll drop down into the bilge, possibly along with the washer. I was able to put a wrench on the bolt heads, and unscrew the nuts from the back. The wrench fell off a few times, but it wasn’t terrible. I had help reinstalling though. Having a second set of hands makes it a breeze. If you’ve got a buddy you can feed pizza and beer to, it’s worth it.

 

[Scottintexas]

it seems like most members who report this problem find the ECU is keeping the injectors open, strange your test with the YDS showed them working but to be honest I think the other members didn't check test with the YDS, maybe there's a difference between YDS test mode and normal operation as far as "closing" the injector,

Have you checked your oil to make sure it's not high or been contaminated with fuel ?

How long was the test ride for ?

very strange the test ride was ok, then the problem showed up, ECU issues are usually come/go type problems,

.

 

[gsnickle]

The test ride was about 20 minutes to include me trying out slow speed maneuvering, high speed turns, wake generation, and docking. I think he replaced the plugs just before we went out, they looked brand new when I pulled them, but black and soaked with gas. Oil was just changed when I took it out on the test ride, so I will check that again when I get home. Could a temp sender or MAP sensor be a problem (I know on other efi systems they can lead to really bad over rich conditions, but I do not know these engines)?

 

[gsnickle]

Well, my boat keeps getting better and better. The oil has a strong smell of gas on the dipstick, so I guess that an oil change will be forthcoming before testing ecu swaps. I thought I heard some bearing noise from the port engine (it was hard to tell if it was the engine or drive shaft). Pulled the pump to find that it did have bearing noise but from the midshaft bearing. Lord help me! I have no idea what to do with that problem, but did get to see that the impeller has been hitting the wear ring and the shaft has two grooves in it at the splined side of the shaft. I am guessing that none of that is a good thing, and I will be ordering new parts. Anybody have any suggestions?

 

[Scottintexas]

sounds like somebody sold you a broken boat, sorry to hear that,

gas in the oil definitely sounds like the injector is staying open, in the past most members have found the ECU is causing this, not bad injectors,

I'd get the ECU straightened out, maybe take the time to switch ECU's and confirm, change that oil before you do any more testing,

I'd like to see the picture of the impeller issues before you do anything with them,


.

 

[Scottintexas]

we have a couple of threads about repairing/replacing the ECU, there is a shop the fixes them, it's not a common thing,

 

[gsnickle]

Okay, here is where the impeller was striking the wear ring in two places...

 

[gsnickle]

Well, you guys were right. I swapped the ecu's tonight. The Port engine ran well (at idle for about 1 min) and the other ran rich. I will now change the oil and filter on both, and then tear into the mid-shaft bearing housings. I don't like the noise that the bearing are making with the long shafts out. Any suggestions on how to get them out? I guess I decouple the water line, exhaust, and loosen the wire loom and slide the engine forward until I get the coupler disengage. Then take out the bearing housing. rinse and repeat. Any tricks to this? Thank you for all the help.

 

[dgfreeze]

At least you found the issue, and it's not too terrible. Regarding the intermediate bearings, I haven't had to change mine yet, so I'm not speaking from experience, but I've seen a lot of threads where people had to do just what you described. Just be careful, as the engines have shims under the mounts to make things align properly. If you look under FAQ at the top, you should find some threads on it, and you can also do a search, and I'm sure you'll find more threads than you bargained for. With the impellers/housings, it looks like you've got some dissimilar metal swelling, which has affected the housing. I presume it's still hitting, and it's not just evidence of a previous issue, like a bad bearing in the cone?

PS, you got a service manual?

 

[gsnickle]

No service manual yet, and I spin the impeller by hand and it still hits a drag point when the impeller passes the two spots. I am thinking of redoing the whole drive line from the coupler on back to shark fins, just to have the peace of mind with my family out on the boat. I know this is a wasteful way of approaching the issues that I have found, but I am an engineer that grew up working on offshore boats and worked with space launch systems in the military. Having a hard time letting go of the nagging feeling that something else in the drive line will give it up at the worst possible time. I am reading all I can about the midshaft bearing, and I did come across the shims, and I ordered a set in case the coupler is out of alignment when I re-install it (cheap way of making sure that it will not need them by having them on hand ). I am learning allot about the boat and the jet pump things, so that is a good thing for me, but a poor thing for my bank account. I really appreciate all the help that I get from this forum. You will know when I am getting past my paranoia about not knowing enough when I start asking about increasing the performance of the boat/engines (I also drove an built race cars in my past).

 

[dgfreeze]

Lol, I could tell you're no stranger to a wrench, so that's a good thing, and you'll be fine doing the work yourself. They're really not bad at all, and very simple to work on. Also, they're actually very reliable in general, so once you get things squared away, you should have yourself a good, dependable boat. If the impellers are currently hitting, you definitely have swelling on the housing, which requires replacement. You can get another one just like it (aluminum housing with a stainless steel sleeve), or you can purchase all stainess housings. I forget who makes them, maybe Impros...? I will say, from what I can see in the pic, it looks like your impellers are in great shape, as long as there was no damage done where it was hitting the housing.

I'll send you a PM also...

 

[gsnickle]

What is the opinion to the use of gear oil in the short shaft bearing? I have read the posts about the impeller bearing and it seem to work well there.

 

[buckbuck]

If you are referring to the bearing under the cone a number of us have switched to a grease/gear oil concoction. @Bruce did a nice write up on it.

 

[Bruce]

1. I would stop running the engine until the ECU and injector problem is resolved. Having an ECU rebuilt is much less expensive than replacing an engine.

2. I have been running gear oil in my duct housing bearings for 5 years without a problem. I do top it up most years.

https://jetboaters.net/threads/changing-yamaha-jet-boat-pump-duct-housing-bearings-and-switching-to-oil-bath-lubrication.10155/

 

[gsnickle]

I was referring to the bearing that sits just aft of the coupler behind the engine. I have read the threads on the impeller bearings behind the cone, and was wondering if anybody has done it with the coupler stub shaft bearing.

I will not be running the engines anymore, just ran it long enough to determine if the ecu was at fault for the rich/fouling condition. I am waiting on the oil filters now. I do understand the effect of gas in the oil, all sorts of bad things follow this condition, and none of them are cheap. Thank you for the advice though.

 

[Bruce]

I was referring to the bearing that sits just aft of the coupler behind the engine. I have read the threads on the impeller bearings behind the cone, and was wondering if anybody has done it with the coupler stub shaft bearing.

I am not aware of anyone using oil for part number 61X-G5332-00-00 described as "Bearing Housing". That part is minimally greased to keep it moist rather than as a lubricant.

 

[dgfreeze]

The bearing assembly right behind the engine, that holds the shaft as it goes through the back wall of the engine compartment is generally referred to as the intermediate bearing. As Bruce alluded, the grease in that housing isn't really there to lubricate the bearings, it's primary purpose is to prevent moisture from entering that cavity/housing. Do not overgrease it, as it is possible to blow out the seals of the bearings.