Fuel Leak + No Spark Plugs but runs great - help - 115 HP

[lncovert]

Hi, I have a 115 HP Johnson outboard (either 1979 or 1981) (the title says it's an '81 but the manual says it's a '79, so I don't know which one it is.

Here is my problem. I noticed my brand new fishfinder transducer mount plastic was deterioating. Then I realized it's from fuel dripping down from the scupper drain hole in the transom. So I tracked it back to fuel leaking from inside the engine. I took the cover off and the fuel isn't leaking from a line. It is leaking from some sort of metal reservoir or case near the front of the motor on the bottom side. Does anyone know what this case is and how to fix the leak? It looks like there is a seal there, but I'm not sure.

Also, I looked on the back of the motor and there are what look like 2 spark plug leads that are dangling free and 2 empty threaded holes where it looks like 2 spark plugs should be screwed into. But the weird thing is that the engine has ran great and I've never had problems with it. How can this be? I'm assuming there must be more than 2 cylinders for the engine to be able to run with 2 missing spark plugs. Does anyone know how many cylinders are in a 115 HP Johnson outboard? I'm very new to engines.

Thanks for all of your help.

Lance

 

[lncovert]

Re: Fuel Leak + No Spark Plugs but runs great - help - 115 HP

Update on last question:

I checked the engine again and noticed that on the back of the engine on the right side there are 2 missing spark plugs, but on the back left there are 2 spark plugs in place. I guess this means there are 4 cylinders but 2 of them aren't firing because there aren't spark plugs in these. I haven't touched the engine since I bought the boat, so does anyone know why someone would leave off 2 of the 4 spark plugs? If I put them back in, could there be a problem (like those 2 cylinders are locked up) or something?

Also, does fuel deteriorate plastic, because the leaking fuel has deteriorated my fishfinder transducer mount. My first one did the same thing and I thought it was because it was old. Then the brand new one has the same deterioration, so it has to be the fuel leaking onto it. Any thoughts?

Thanks!

 

[lncovert]

Can engine run with only 2 out of 4 spark plugs?

Can engine run with only 2 out of 4 spark plugs?

My engine only has 2 out of 4 spark plugs. It was like this when I bought it apparently, and it has been running great for the past year. Is there a reason why someone would've taken out 2 of the 4 spark plugs? Thanks for your help...I am very new to engine troubleshooting.

 

[F_R]

Re: Fuel Leak + No Spark Plugs but runs great - help - 115 HP

This almost sounds like a gag question, but I'll be nice and try to believe you. So you seriously have been running it on only two cylinders and haven't noticed any difference huh? Let's just say you are lucky that thing hasn't erupted into a ball of flames. You are pumping atomized fuel and air mixture out those missing plug holes. Extremely flamable stuff ready to blow sky high with a tiny spark. Of course it is dripping gas, where else would it go?

Clean that mess up with some sort of solvent and hose it off and let it dry in the sun. Put the missing plugs in and see what happens. But hold onto your seat, it will go MUCH faster.

Oh, and do something about that transducer location.

 

[lncovert]

Re: Fuel Leak + No Spark Plugs but runs great - help - 115 HP

Thanks for your help. No, that was not a gag question. I am a complete novice when it comes to engines. I bought the boat over a year ago and today was the first time I have taken the cover off of the engine to take a look. Dumb, I Know. I have taken the boat out maybe 15 or 20 times since I bought it, and I have never had a problem with the engine. Well, one time the remote control unit started buzzing (meaning it was overheating) and I shut off the engine for 30 minutes, and then it ran great the rest of the day. After reading your post, I am thinking that since 2 spark plugs were missing, some of that gas vapor coming out of the holes did ignite and maybe that caused the engine to overheat. Is that possible? I mean, my engine cover didn't go up in flames or anything. One thing I do know, is that I am really impressed with Johnson now.

I will definitely put those 2 missing plugs in this week and I am pumped about taking it out next weekend to see what it can do with 2 more cylinders going. The previous owner told me the max speed was about 50 mph, but my max speed is only 32 mph. I'm guessing it's because of the 2 missing spark plugs. Anyway, thanks for the help!

 

[lncovert]

Does Gasoline deteriorate Plastic?

Does Gasoline deteriorate Plastic?

Hi, I have had 2 fishfinders. The first one came with the boat and was probably from the 80's. I noticed that the plastic was really damaged (deteriorated). I thought it was from the age. Then one day, the transducer ripped off in the water because of this. I bought a brand new fishfinder and transducer. I installed it in the same place (directly below the bilge hole in the transom). This was about 3 months ago. Today, I noticed that the new plastic transducer mount was really deteriorated. Also, all of the paint was bubbled up and I realized gas was trickling down from the bilge hole due to a small leak in the engine.

Here is my question.

Does gasoline or gasoline/oil mix (I have a 2-stroke) deteriorate plastic? It looks like it does. But then I think: surely this can't be because we store gasoline in those red plastic containers.

Thanks for your help.

 

[JB]

Re: Can engine run with only 2 out of 4 spark plugs?

Re: Can engine run with only 2 out of 4 spark plugs?

LIEBE HIMMEL!!

Please tell us what model and brand engine you have, Incovert.

 

[cary00silve]

Re: Does Gasoline deteriorate Plastic?

Re: Does Gasoline deteriorate Plastic?

It depends on what type of plastic it is. Sure it doesn't deteriorate gas cans but try holding gas in a plastic cup or in a plastic water can. It will melt it in a matter of minutes if not seconds.

 

[lncovert]

Re: Can engine run with only 2 out of 4 spark plugs?

Re: Can engine run with only 2 out of 4 spark plugs?

Hi, sorry, I have a 115 HP, Johnson outboard (either '79 or '81). Thanks.

 

[gregr1971]

Re: Can engine run with only 2 out of 4 spark plugs?

Re: Can engine run with only 2 out of 4 spark plugs?

My engine only has 2 out of 4 spark plugs. It was like this when I bought it apparently, and it has been running great for the past year. Is there a reason why someone would've taken out 2 of the 4 spark plugs?

WOW!!, AND I THOUGHT I HAD PROBLEMS..........

 

[Scaaty]

Re: Does Gasoline deteriorate Plastic?

Re: Does Gasoline deteriorate Plastic?

Also, all of the paint was bubbled up and I realized gas was trickling down from the bilge hole due to a small leak in the engine.
Not gonna touch it...
(worried about the "plastic"??...lucky it wasn't a 4th July unplanned bang...and not on the 4th.. .....)

 

[Willyclay]

Re: Fuel Leak + No Spark Plugs but runs great - help - 115 HP

I guess the old saying is still true; you have to really try to kill a two stroke engine!

 

[luckyinkentucky]

Re: Does Gasoline deteriorate Plastic?

Re: Does Gasoline deteriorate Plastic?

I wouldn't worry about the plastic at this point. You need to find the source of your fuel leak. That can be deadly!

 

[tashasdaddy]

Re: Fuel Leak + No Spark Plugs but runs great - help - 115 HP

i think you better by a manual, and make it your best friend, until you read all of it. Maintainance is the #1 thing to make a 2 stroke last, neglect it, and you will have a melted mass of metal. have you changed the inpeller, i sure you haven't.

 

[lncovert]

Re: Fuel Leak + No Spark Plugs but runs great - help - 115 HP

I will buy a service manual. I know very little about engines, but I'm about to learn. No, I haven't changed the impeller...I don't even know where that is (I'm guessing inside the water pump).

Thanks for your help.

i think you better by a manual, and make it your best friend, until you read all of it. Maintainance is the #1 thing to make a 2 stroke last, neglect it, and you will have a melted mass of metal. have you changed the inpeller, i sure you haven't.

 

[rudedude]

Re: Fuel Leak + No Spark Plugs but runs great - help - 115 HP

As posted above the raw fuel is more than likley from the two open plug holes.

The water pump is located in the lower unit, there are normly 3 bolts on each side of the cavitation plate ( the flat looking plate just above the prop and bullet shaped gear houseing) There is a hidden (somewhat) bolt under the "fin" looking thing just above the prop.

If you have a manual it is a simple process to change the water pump and houseing, with out a manual you will make a mistake (maybe) that will cost you.

As you have found out the motor will run with missing plugs but it will not run long without water cooling it from the water pump. Good luck

You get the plugs in and you will be shocked as to how much faster the boat will go.

 

[lncovert]

Re: Fuel Leak + No Spark Plugs but runs great - help - 115 HP

Ok, thanks for your help! I am excited to see what power it will have with all of the spark plugs in.

 

[spy1309]

Re: Fuel Leak + No Spark Plugs but runs great - help - 115 HP

LOL I wonder how come your boat is stil floating, like F_R said you were a bomb riding the waves lol.

 

[noelm]

Re: Fuel Leak + No Spark Plugs but runs great - help - 115 HP

OK then, this is for real?? I reckon that even for a very first time boater, the motor must have been vibrating that bad with only 2 plugs installed that you MUST think something is wrong! but I guess it could be so!

 

[iwombat]

Re: Fuel Leak + No Spark Plugs but runs great - help - 115 HP

Once you take the plugs out, you don't have any compression to fight. It probably ran okay, just a much bigger crank assembly and some added piston friction to overcome. I've seen V-twins cut in half that way for flat-tracking w/a plate over where the rear jug used to be. Works fine. You start losing performance when you've got compression and no power being generated. Probably generated about 45hp or better.

With the missing two plugs and dangling spark wires, it was only a matter of time until the one bank turned into a badly designed sidewinder boost.