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

[lncovert]

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

The sparks on the 2 cylinders were orange...maybe that is why I couldn't tell much difference with the new plugs in. Oh well, it's ok for now.

Wish I were there to watch!

Later, verify the spark color, orange is weak and will limit HP and rpm. That should be addressed should you survive 'testing'.

Take Care

 

[dajohnson53]

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

The sparks on the 2 cylinders were orange...maybe that is why I couldn't tell much difference with the new plugs in. Oh well, it's ok for now.

Spark testers need to be set to a certain spacing for a proper test. At that gap, the spark should be a sharp, blue snap, not dull, weak or orange.

It is a way to troubleshoot weak engine performance - weak spark, indicated by the above test, can point you toward the source. For example, on my engine, each spark plug is fired by a coil. I could discover the weak spark, then exchange the coils and see if the weak spark followed the coils. Exchanging the coils was dead easy.

I would suggest that as your next step. Find out what the tester gap should be set at (search this forum for "spark tester" - there's been many posts, many mentioning correct gap). Then, if any of your sparks is not bright blue and solid, see if you can trace the source of the problem to a coil.

You can also do a similar spark strength test by removing the spark plug wires one at a time as the engine idles, listening for change. A weak spark won't be noticable when you remove the wire. A strong spark will result in noticable change in engine sound when removed.

Use insulated pliers and rubber gloves to avoid shock (BTDT).
Also as others have said, you need to check compression.

 

[commonarcwelder]

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

2 dead cylinders on that motor would act more like a 9.9hp johnson trying to get it on plane. much less run 32mph!! somebody has played a cruel joke on you my friend.......kind of like my hunting buddy did to me (turned my scope adjustments on my 300 win. mag. a few clicks last year on opening day) he' ll never do it again.

 

[Silvertip]

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

First we hear this boat does 32 MPH on half its cylinders and now he's slalom skiing behind it. If you weighed 15 pounds I can buy that. If you are an average 170 pound adult male I doubt this story.

 

[lncovert]

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

Haha, I love the fact that no one believes me. I have slalomed behind it. I weigh 145-150 lbs. I had to drop a ski though...it didn't have enough power to pull me up out of the water with just 1 ski on, so I just drop one. That's another reason why I think 2 of the cylinders aren't working...my parents' old evinrude 45 or 55 HP engine would yank them out of the water with only 1 ski on, no problem. So, I think 115 HP should be able to yank me up with half a ski on.

I don't think anyone played a prank because none of my friends are here anymore...if someone took out the plugs, then it was a stranger committing a crime. I'm actually surprised it hasn't gotten broken into/stolen yet...maybe it has and all they stole were $2 plugs.

It all boils down to this: Is 34 MPH a reasonable speed for a 115 HP engine on an 18-foot boat with a 13x19 prop?
If that is the maximum speed that y'all would expect to get out of a 115 HP, then someone must have stolen the plugs at just the right time. So when I replaced them, I noticed very little difference. I can sleep easy if this is the case. But then I'll have to keep a watch on my boat at night.

First we hear this boat does 32 MPH on half its cylinders and now he's slalom skiing behind it. If you weighed 15 pounds I can buy that. If you are an average 170 pound adult male I doubt this story.

 

[kenmyfam]

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

Put one more plug in and try barefoot !!!!!

 

[ondarvr]

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

You don't need to go to the lake and test it, just pull the 2 plug wires and run it on muffs in the drive way. If it starts and runs at idle about the same as it did in the water, then maybe you were running on only two, if it won't start or does start but won't idle then you know it always ran on 4.

You can also pull one wire at a time and see how it runs on any combination of three, it should run a little rougher, but about the same on any three of them. If it dies, or there is little or no change when one is pulled off then you know you have other problems.

 

[clemsonfor]

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

he has already said he has no hose hookup at the apt. to run on muffs!

-Nate

 

[CharlieB]

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

It's very hard to say what your WOT speed should be, it all depends on the running weight of the craft, state of tune of the motor, gear ratio, prop size, weather and water conditions.

You're doing OK,but a weak spark on two cyl's isn't firing those cyl's to maximum capacity, the engine will pull (rev) under load up to the limit of it's ability. Finding the weak ignition component, replacing it, you should gain a noticable amount of power and speed.

Do you have a tach, if so, what is the WOT rpm in forward, and can you check your speed with a GPS? Some cell phones have a GPS but I don't know if they have the speed capability, may only be location.

You could try switching the ignition modules from one side to the other, see if the weak sparks also switch sides. That should tell you if it is the ignition module, if no change try switching the coils to the other side. If still no change then it is the stator feeding the modules.

 

[commonarcwelder]

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

If he is talking about the boat he has in his signature picture....I would have to say that 32 MPH is very good with a 115 johnson! Put your spark plugs back in the thing and leave it alone.......

 

[lncovert]

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

It is the boat in my signature. 18-foot.

CharlieB, I do have a GPS and the GPS speed at WOT was 35 MPH (I do no have a tachometer though). The previous owner said it would do about 50 MPH, but maybe he was exaggerating.

I'll probably just test for spark again and see if it is orange or blue and if it is orange, maybe I'll order an ignition coil or two off of iboats. If all 4 spark blue, then I'll just leave it be and keep practicing my slalom.

If he is talking about the boat he has in his signature picture....I would have to say that 32 MPH is very good with a 115 johnson! Put your spark plugs back in the thing and leave it alone.......

 

[Molaker]

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

I ran a prop calculator ("www.rbbi.com/folders/prop/propcalc.htm") using 5800 RPM with a 2.25 gear ratio (I think that's what your motor has), a 19" pitch prop with .01 (zero) slippage (not possible, only theoretical) and the result is 45.9 MPH. Basically, that means that's the very best you could expect from your motor at 5800 RPM on ANY boat with a 19" prop. Chances are, you prop will have far more slippage, more on the order of .3 which calculates to 32.5 MPH or just about what you are getting. That means you would have to turn 5800 RPM (approximately) on 2 cylinders. Adding 2 more cylinders would most certainly over tach your engine.

I still think somebody did you dirty in the parking lot.

 

[CharlieB]

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

Test before you buy, there is NO RETURN on electrical parts. Those coils may be fine.

Re-read my previous post about switching parts from one side to another to see if the weak spark also switches sides.

Test, retest,Diagnose, buy only the correct part, save MONEY!!!!!!!





Some people think I'm economical, my wife thinks I'm a cheap S.O.B.

 

[lncovert]

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

You had me 100% convinced for a few minutes. Then I saw where my manual says the gear ratio is 13:26 or 2. Using those same numbers the max should be 51.7 MPH. Adding 1" of pitch for cupped prop gives a max of 54.4 MPH. Then adding a more realistic 10% prop slip brings that down to a max of 49.4 MPH. Previous owner said "about 50." That's pretty close.

I'll have to test those sparks again and see what I get. I'll double-check before I go and buy a coil. Thanks for the advice.

I'm hoping that no one stole the plugs for 2 reasons:
1) so I can get more HP out of the engine
2) so I can sleep better at night and not worry about hoodlums in the parking lot

I ran a prop calculator ("www.rbbi.com/folders/prop/propcalc.htm") using 5800 RPM with a 2.25 gear ratio (I think that's what your motor has), a 19" pitch prop with .01 (zero) slippage (not possible, only theoretical) and the result is 45.9 MPH. Basically, that means that's the very best you could expect from your motor at 5800 RPM on ANY boat with a 19" prop. Chances are, you prop will have far more slippage, more on the order of .3 which calculates to 32.5 MPH or just about what you are getting. That means you would have to turn 5800 RPM (approximately) on 2 cylinders. Adding 2 more cylinders would most certainly over tach your engine.

I still think somebody did you dirty in the parking lot.

 

[lncovert]

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

Thanks, I will try to switch the coils from one side to the other and see if the weak spark follows the coil or not.

Test before you buy, there is NO RETURN on electrical parts. Those coils may be fine.

Re-read my previous post about switching parts from one side to another to see if the weak spark also switches sides.

Test, retest,Diagnose, buy only the correct part, save MONEY!!!!!!!





Some people think I'm economical, my wife thinks I'm a cheap S.O.B.

 

[roofcock]

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

I TOO THOUGHT THIS POST WAS B.S. if not, then i will tell you what i think about your fuel leak. the way you describe it the needle valve in the float bowl/ bowls is stuck. the fuel is pumped into the cylinder by the turning crank. however the float bowl of the carb has a valve that stops the fuel from coming in from the tank. as the fuel level in the bowl rises it pushes the float up. (hence the name, it floats) closing the valve that is attached to the float and closes the orifice the fuel is flowing in from. if it sat a while the fuel could have gummed it up and you are not geting the orifice to seal with the needle valve. therefore filling the bowl beyond capacity and causing the fuel to run out. buy a manual take the carbs apart and clean them. very simple procedure. but dont look at the manual as you are doing it. read the section in the manual about this and understand it. then use the manual as a point of reference. READ AND UNDERSTAND. i say it like that because you sound very inexpierienced with a wrench, screwdriver, multi-meter, etc... READ IT READ IT READ IT

 

[roofcock]

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

I TOO THOUGHT THIS POST WAS B.S. if not, then i will tell you what i think about your fuel leak. the way you describe it the needle valve in the float bowl/ bowls is stuck. the fuel is pumped into the cylinder by the turning crank. however the float bowl of the carb has a valve that stops the fuel from coming in from the tank. as the fuel level in the bowl rises it pushes the float up. (hence the name it floats) this valve is attached to the float and closes the orifice the fuel is flowing in to. if it sat a while the fuel could have gummed it up and you are not geting the orifice to seal with the needle valve. therefore filling the bowl beyond capacity and causing the fuel to run out. buy a manual take the carbs apart and clean them. very simple procedure. but dont look at the manual as you are doing it. read the section in the manual about this and understand it. then use the manual as a point of reference. READ AND UNDERSTAND. i say it like that because you sound very inexpierienced with a wrench, screwdriver, multi-meter, etc... READ IT READ IT READ IT

 

[ondarvr]

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

So what have you found?

 

[commonarcwelder]

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

Yea. Inquiring Minds want to know!!

 

[clemsonfor]

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

well have we laid this problem to rest or did you just say oh well i can ski and am happy, leave it?