She Idles Fine on Muffs But Not In Water

[Bergertime]

All,

Had another interesting occurrence yesterday (and occurred last weekend too) when I was out fishing and I was hoping for some quick advice.  My OMC 225 Carb was having problems idling in the water.  She started right up and ran fine during the warm up cycle but after she's warm she sputters out and dies fairly consistently after startup in abt 1-3 seconds.  She always starts right up after (I have to give her some throttle in neutral) and runs fine underway.  

Interestingly she idles fine on muffs.  Ran her at idle for ten minutes at home and did not sputter once.  Some of my research indicates that the reduced backpressure out of the water is the contributor here.  My question is..  Is this likely an in the water idle adjustment or are there deeper issues here at the making such as timing or other complex tuning needs.  I just changed the spark pugs as mentioned under a different post.  Thoughts?

B

[fitz73222]

Hey Berger,

What's your in gear idle speed in the water? How does it compare to what it should be? I don't have the spec in front of me but I would guess around 700-750 rpm's. Sometimes the idle speed is stated on the front of your airbox cover along with the timing and max rpm numbers. If the idle speed has changed for no reason, look at the plugs carefully and see any abnormalities for carbon, very clean (water cleaning the plug) or any evidence of aluminum transfer. The plugs should be a variant of brownish tan with a slight amount wetness from fuel. When's the last time you decoked the powerhead with valve-tech or the OEM brand of spray solvent to remove carbon deposits from the rings, piston tops and combustion chamber? I am a diehard believer of this process at 100 hour intervals and it makes a huge difference in idle quality and bottom end improvement. I'll bet your big looper could use a good internal cleaning. If you decide to do it; Dont breathe the fumes! It will smoke like crazy so get the wind or a fan at your back. The stuff is naptha based with other chemicals and plays hell on your lungs, read the warning label. The other obvious checks are filters and the presense of water in the fuel. A quick compression test wouldn't hurt. I seem to remember your looper ran pretty low compression around a 100 psi or so. Georgie would know if he jumps on this. Turn the engine over only 4-5 compression strokes with the throttle butterfies held wide open for an accurate measurment.

[Bergertime]

Thanks Fitz.  I just changed the plugs (factory spec) and they maybe have 5 hrs top on them.  I have had the boat for a year now so it's time for an annual service of sorts but I try to do as much as I can on my own (total mechanical newbie).  Outside of changing the plugs and a primer solenoid check nothing really has changed except performance.  I did drain the bottom of my Racor filter water/sep yeaterday and there was no sign of water either in the clear bowl of in container.    Do you mind providing some more detail on the cleaning routine that you mentioned.. What to use and the how to do it?

Thanks,

Bruce

[fitz73222]

The cleaning process is pretty straightforward; you remove the airbox cover in front of the carbs to expose the throats of the carbs. Unless your engine is really carboned up one spray can should do it. its a 16oz can with a spray tube. You start the engine on the flush, let it warm up at set it at about a 1000- 1200rpm fast idle. You have six throats on your engine. Start with the top left and move to the right and stair step your way to the bottom right. Spray enough tuner into each venturi until the engine starts to slow down and bog then move to the next, keep repeating the process until you have used about 90% of the can. Try not let the engine stall while you're doing this but dont let it clear itself out. The goal is to get the engine really pickled with this stuff and not burn it all the way. Then take the remainder of the can an flood it with the remaining in as many throats as you can and now try to stall it out, if it wont stall just turn the key off and let it sit for a 1/2 hour, then fire it back up. You wont believe the crap that's going to come out of it. Now the best thing to do is while the engine is soaking, take it to the ramp, launch it and go nail the throttle. But if you can't get to the ramp just let it run in the driveway for about 15 minutes at fast idle to clear itself out. Your driveway will turn  black with soot and oil tadpoles belching out of her. Everybody makes this stuff and it's all the same chemistry. Valve-tec from West Marine, Power Tune from Mercury, Yamaha and BRP have their own version so whatever is convenient for you. Let the neighbors you care about know what your up to so they don't call the fire dept for the hazardous stink coming from your front yard! AND DON"T BREATHE ALOT OF THIS !

[Bergertime]

Thanks Fitz.. That's what I needed.  I'll give it a try and see if it helps.  What are thoughts about the slow idle setting and the fact it idles fine on the hose?

Bruce

[fitz73222]

Thanks Fitz.. That's what I needed.  I'll give it a try and see if it helps.  What are thoughts about the slow idle setting and the fact it idles fine on the hose?

Bruce

It's normal in high humdity and summer heat to have a disparity in idle quality between the driveway flush and in the water with back pressure in gear idle speeds. 150-200 rpm would be typical. So if your on the fringe, it could stall in the water. You could bump the idle speed up in the water and in gear to improve the idle quality. Down here in Florida, the humidity and heat gets so high that a change in mixture or idle speed can sometimes be necessary. Next time you're out check the in gear idle speed on your tach and see if its falling into the 500-600 rpm range which could lead to a stall. Of course, timing, fuel quality and general condition of the engine also play a role. I wouldn't do anything until you clean the lungs of this engine out with the juice. Most people never do this to their engines and they slowly start running worse and you don't realize it until she starts acting up. Its just like brakes in your truck, it's a slow process until you really need to lean on them to get it to stop. You're going to like the results of "pickling your powerhead" Your rings and pistons will be forever greatful! If there is another issue, we'll find it.

[Bergertime]

Thanks for the additional info.  I will try the cleaning tomorrow after work and take her out on the water and see if it helps.

Have a good evening..

B

[pigbike]

Fitz,
Is Seafoam the same stuff. I hear alot about it for decarbonizing a engine.

[fitz73222]

Fitz,
Is Seafoam the same stuff. I hear alot about it for decarbonizing a engine.

Some guys are using it on the antique outboard forums I'm a member of but it seems to help free stuck engines, clean varnished gas tanks  and pour in your gas tank to help clean the fuel system. I've never used it. I have used the products I've mentioned earlier for the last 20 years with excellent results. So to honestly answer your question, I really don't know if its the same or not. The Mercury Power Tune, OMC Engine tuner, Valve-Tec or the Yamaha equivalent have been around for at least 20 years that I can vouch for and they work very well.

[pigbike]

Ok thanks.

[Bergertime]

Well guys..  I tried to get to the engine decarbing yesterday but I had a serious onslaught of other issues related to fuel delivery that I don't have the energy to type.  It suffice to say that I was highly frustrated.  I should have the parts (Clear Racor fuel bowl) tomorrow so I can prime and get my engine started for the other.  Ugh.. nothing is ever easy!

B

[Bergertime]

Well, got some good news... And more ?s

Last night I worked on her and finished the replacement of my Racor Filter / Water Sep.  Warning - If you are buying and installing one of these kits on your boat make sure that you can disassemble it and lube the gaskets b/f installation.  The one that I had (barely a year old) took an act of congress to get off the mount and I could not get the collection bowel off without damaging.  They are $45 to replace if you can separate them from the filter.

Fitz- I used the de-carbing spray and adjusted my idle up just a tad via the screw on the throttle linkage that pushes against the block.  Took her out to Tampa last night for dinner with GF and she ran great with no idle issues.  I have a tach issue that I need help with but I will start a new thread for that.  Thanks!

B

[Capt. Bob]

I could not get the collection bowel off without damaging.  They are $45 to replace if you can separate them from the filter.

Never tried this but it may help, though I don't think I'd use it on my intestines.
http://www.foreandaftmarine.com/62-RK22628.htm

[Bergertime]

Cheaper than the new collection bowl but unfortunately I already replaced it.  When I put it on I was sure to lube the o-ring and snug it up hand tight.  It's worthy to note that tried to find a whole unit where I could remove the filter the bowl by hand.  Tried two at different stores and could not remove the filter or collection bowl by hand at either location.  Not sure why they come from the manufacturer like that b/c whoever buys it will be in the same place down the road as I was..  

B

[Capt. Bob]

 Tried two at different stores and could not remove the filter or collection bowl by hand at either location.  Not sure why they come from the manufacturer like that:shock:

Trying to move those wrenches.