Just a hopeless cause?

[StriperChaser]

I've got random low compression on one cylinder of my Johnson 112 causing a misfire. I'm pretty sure the problem comes from years of not decarbing the engine and the piston ring is sticking. Sometimes it runs 100% then other times that one cylinder doesn't fire when first coming up on plane. Always runs great at WOT. I've done the decarb with Seafoam a few times which helped tremendously but is only short lived and the problem returns after it sits for awhile. It does seem to do a little better each time out but problem has always come back so far. If I keep running Seafom through it will this problem eventually solve itself, or is it just a hopeless cause?

 

[alcan]

Re: Just a hopeless cause?

Since we can't see inside your motor. How could we tell? What are you compression readings. If you have a damaged cylender it won't get better with out an over haul. Have you checked your ignit. and fuel systems?

 

[StriperChaser]

Re: Just a hopeless cause?

Well that's exactly the point. I can't see inside without taking it apart. I've checked the comp and had 120, 120, 120, 40. Then checked it again and had 120, 120, 120, and 115. It's pretty irratic on the bottom right cylinder. I've rebuilt carbs, replaced the fuel pump, replaced the thermostats, and checked the spark and ignition. The problem is in that one cyl. If it was totally shot, it would stay low comp. Plugs stay nice and clean burning the Seafoam through the fuel. Sure appears to be a carbon problem but I'm no expert. With the help of this board and the repair manual I've learned more about this engine than I ever wanted to know. Was just hoping to avoid a costly rebuild if possible.

 

[ob1jeeper]

Re: Just a hopeless cause?

IF as you suspect, there is carbon or ?? sticking the compression rings occasionally, then a solvent that can attack hardened carbon, without attacking the seals would be a reasonable thing to try. Apparently you've found some short-term success using "seafoam" (whatever that is).<br /><br />I'd try bringing the piston up high in the cylinder (take all the plugs out then rotate the motor by hand, and watch the piston until you get it "high" enough to get it to "seal" off the ports. Then get some rust penetrant type material (or perhaps even your seafoam stuff, and squirt as much into the cylinder as you can get into it, then put the plug back int that hole finger tight only, to keep the "light ends" of the solvent material from evaporating off, and let it sit over night (or even a couple of days, if you can... The longer the better. AND if you could position the motor, such that the material covered the entire circumference of the ring, the better as well).<br /><br />After you've let it sit for "a while", pull the plug out, and use a baster syringe, or other similar device to suction out as much of the material as you can, before cranking the motor over with the starter only and NO plugs in the cylinders (you don't want it to fire just yet), until you have ejected almost all of the excess solvent material. (four or five revolutions of the engine with the starter should suffice, if it's spinning pretty freely...)<br /><br />Then I'd put one light squirt of 2-stroke oil in each cylinder (but especially this one), re-install the plugs, and give it a try... If the rings were stuck by excess gum/carbon,they should be better than before.<br /><br />Otherwise, you just might have to pull it down, and have a lookee see...<br /><br />GOOD LUCK Obiwan Jeeper

 

[alcan]

Re: Just a hopeless cause?

I agree with jeeper, Soak it down with that seafoam. When you get done, go run the hell out of it. A couple tanks of fuel worth. If you stiil have the problem then it's over haul time.

 

[jasonnb]

Re: Just a hopeless cause?

I agree as well, except I would shock it with seafoam. This is the process I use and have had great results, but others may be more cautious. I pull the carb cover off my '76 Johnson v4 after warming it up on the hose and spray seafoam straight down the carbs until it chokes. It takes a bit since seafoam is about 64 octane. I then pull the plugs and shoot a bit in each cylinder. Put the plugs back in and leave the wires off. Turn the motor over a couple times. wait about 1-2 hours, reconnect the plugs, and fire it up. You will see all kinds of black junk blow out the exhaust. If this hasn't been done in a wile, I repeat the process once more. As I said, this is the process I use and have never had fouled plugs or any other engine problems in the 3-4 years I've had this horse, but use at your own risk.<br /><br />You're not at "hopeless" yet! I believe she may yet recover if the problem is carbon. These V4's seem to darn near run forever if nothing breaks.<br /> <br />jeeper, it seemed you were asking about seafoam. It is much like OMC Engine tuner, only it is readily available at most auto parts stores. It comes in spray and pour forms.

 

[jasonnb]

Re: Just a hopeless cause?

By the way, the seafoam will clean the plugs as it burns, so they may not show anything.

 

[ob1jeeper]

Re: Just a hopeless cause?

To jasonnb... Thanx for the info... I have VERY limited experience with outboards, so it's always interesting to hear some of the brand names, folks have for various needs/uses.<br /><br />StriperChaser... Another solvent that may work "ok" for the soaking, is over-the-counter fuel injector cleaner... readily available from your local auto parts store... Just be sure to expel as much as possible, and lightly re-lube the cyl walls, before tring to re-start the motor... Don't want the cyl walls to be "dry" of proper lubricant... <br /><br />Keep us tuned in on how & what works... GOOD LUCK Obiwan Jeeper

 

[StriperChaser]

Re: Just a hopeless cause?

Thanks for the advice guys. When I first found the low comp in that cylinder I did as you have suggested. I sprayed the Seafoam through the carbs until it choked down, removed the plug and flooded that cylinder with Seafoam and let it sit for a few days. You're right. it blew all sorts of black gum out. I then took a 3 gal portable tank, mixed it more than double strength and ran it at WOT at the lake until that tank emptied. It ran like a champ afterwards. I could stop and take off just like new. Thought I had solved the problem, but once it sat at the house for a few weeks, I again experienced a random miss in that cylinder although not as often. I recently purchased some OMC engine tuner and thought I'd give that a try. Sounds like there may be some hope after all to get that carbon out without a tear down. If anyone does much trolling and doesn't decarb as recommended, I have proof of what it will do. Thanks again.

 

[jasonnb]

Re: Just a hopeless cause?

I kinda wonder if the misfiring could be due to a bad powerpak or coil. A powerpak going bad can do strange things, not with compression readings, but with proper firing.

 

[jasonnb]

Re: Just a hopeless cause?

No prob jeeper. That seafoam is interesting stuff. It was originally designed to decarb outboards as it has a lubricating property, but it also has enough octane rating to be used as a safer starting fluid. It's good for mowers, weedeaters, cars, trucks, rusty bolts, water dispersant, etc. It's like WD-40 with an extra kick. It's much easier in my area to get than actual engine tuner spray since I can pick this stuff up at almost any auto parts place. I even pour it in my truck as fuel injector/intake cleaner. Works great. Seafoam is the pourable, Deep Creep is the spray if I remember right

 

[StriperChaser]

Re: Just a hopeless cause?

jasonnb, I've checked the spark with a spark tester and it showed ok, but I guess a powerpak going bad could certainly be a possibility. It starts and idles fine, runs real smooth at idle and a little over 5000 RPM's at WOT. It started cutting off when shifting into gear and would not pull up a skier this past summer. That's what led to all the work previously listed. After checking the compression, and not getting a consistant reading, that seemed to be the key. Once I went to work decarbing the cylinders as advised by others on this board, I began to see a noticable improvement. I just don't have the time or expertise to rebuild the engine myself. One outboard shop told me it would be better to just replace the powerhead than to rebuild due to his warranty issues. I just did'nt feel comfortable with his recommendation or the cost at the time. The decarbing has made a big difference in the overall performance. I'm going to try soaking that cylinder again as suggested and keep my fingers crossed that I can make this problem just go away.

 

[jasonnb]

Re: Just a hopeless cause?

I don't think you are at rebuild point just yet. The whole misfiring thing just smells of powerpak to me for no good reason. Mine did something similar when it dropped the power pak last summer. It got harder to start and had a noticable power loss every so often. Before I figured out what it was, the power pak let me know by dropping one entire cylinder bank. Tossed a new pak on and she's good as new. I'm just an amateur at this, so take what I say witha grain of salt.

 

[thosch]

Re: Just a hopeless cause?

Hi Chaser,<br /><br />Glad things are looking good for that motor. I have a v-4, and think they are great, with the proper maintenance.<br /><br />I have a comment about the WOT rpm. You stated a little over 5000. Check what the WOT for your motor should be. I repropped to get my WOT up to 5800 from 5200. Now seems to be lugging a lot less, and it should increase service life.<br /><br />Just my opinion. Good luck.

 

[StriperChaser]

Re: Just a hopeless cause?

Hey t.h.,<br />My engine specs call for 4800 to 5200 rpm. I'm running a 17" pitch that seems to be doing a good job of popping the bow up pretty quick (when all's running correctly) and that's with 40 gals of fuel, 30 gal bait tank, 4 batteries and other equipment. I origially had a 19" on and it did lug pretty bad so I bought the 17". I'd be concerned if mine ran 5800 rpm when the specs call for 5200 but maybe that's ok.

 

[DJ]

Re: Just a hopeless cause?

striper chaser,<br /><br />5800 is OK for your crossflow V-4.<br /><br />Use the OMC engine cleaner as per the directions. That stuff is pretty aggresive and will clean the rings.