Logo
FULL SITE MENU

60hp Mercury Outboard 60ELPT0 - Idles fine and then starts running rough at higher RPMs

F

fickesd1

New member
The Engine will idle just fine, then I start driving slow and for awhile it seems fine. Then when I increase the RPM and get closer to Wide open it start jerking and running rough. It continues to get worse and even hesitates when I take it back down to a slow speed and then I limp back to the dock. At first I suspected bad gas even though it was new gas. I ended up cleaning all 3 carbs and they looked pretty good. The bottom carb did have an internal gasket (the one that goes over the main tube in the float bowl chamber that had a rip in it. I didn't have a replacement one so I had to put it back together. Do you think that could be the problem? I also have tried changing spark plugs and fuel filter and a different gas tank. One other thing I noticed and thought was the problem was when I replaced the fuel filter with a clear one, the first time I primed the bulb I saw a lot of junk pushed into the filter. I stopped immediately and pulled the filter and emptied 4 small containers by squeezing the primer bulb with the hose (right before the fuel filter) aiming into a small cup. I did this until the gas was clean and then put everything back together. I assume the junk was from the previous fuel line and primer due to years of using gas with Ethanol ( I replaced that a week or two prior) The other thing I'm questioning is the fuel filter I replaced the original one with a universal inline filter so I didn't know if that could cause a problem. The last thing I checked is the compression and all cylinders were right around 100 psi.

I'm at a loss now and not sure what else it could be. Any help will be appreciated.
 
You went after what I would have recommended, based upon personal experiences. Your old filter was full of crud from just what you said. Happened to me on 2 engines when they passed 10 years of age. What you didn't say was that you replaced the internal fuel lines also. In doing your carbs did you disassemble them to the lowest level and in doing so did you see any black specks....pieces of internal fuel line that made their way into the carburetor(s). I had a problem and it was just that but I accidentally found the one piece causing the problem....it was buried down in the cavity where the high speed jet is located on one of my carbs. Just accidentally hit it at the right angle with 100# compressed air and wala...there it was.

¼" filter port may be too small. My 90 and 115 engines were spec'd at 5/16 diameter lines. Know not size recommended for 60 hp.

On the gasket, it would be leaking fuel if it were a problem. (opinion).

My OEM service manuals say that below 120 PSI you can expect to have problems, but not jerking type things...just low power for the stated HP.
 
Last edited:
Thanks for the reply TexasMark. I have not replaced the internal fuel lines but that is probably the next best thing to go after. At first I thought the crud was just coming from the fuel line from the tank to the outboard but after reading a few more post in the forum they distinguished that the black crud was likely from the internal fuel lines and if it was from the external gas line it would probably be tan. The weird thing was that I didn't see much of anything inside the carbs other than a few little specs. I think I tore town the carb as far as I could and sprayed cleaner in every place I could. And the one gasket that was ripped was inside the float bowl and was the little round gasket (about 1/2" in diameter that went over the middle tube, not sure what it's called). I think I might just buy the carb kit, the correct fuel filter and all new internal fuel lines and try again. I just wasn't sure if I was going after the right thing. I.e. could it be timing, coil, fuel pump, temperature related, etc.... What I can't explain is why it will move along slow just fine until I give it full gas and then when I bring it back down slow it still struggles. I would have thought when I bring it back down to the original speed that was working ok, that it would work good again. Can the fuel pump be dissembled and inspected?

Thanks again for the help
 
Did miss what year your 60ELPTO is?

I have an '85 - 60hp, it has a low and a high speed set of winding in the stater with a separate wires connected to the switch box. It is not uncommon for the high speed winding to fail (causing problems running at high spped). Goto the CDI website they have testing specs for your stater.

Here is a link to a web page that has the CDI 'pdf' file on it
https://www.go2marine.com/troubleshooting-outboard-electrical-problems
 
Another theory I wanted to vet out with you guys. I started the engine and started pulling the plug wires off one at a time. There wasn't a noticeable difference when I pulled the top and middle plug wire off to the sound of the engine, but noticeable when I pulled the bottom plug off the spark plug. Going back to my comment earlier... when I took each carb apart the only thing I noticed out of the ordinary was the bottom carb had the small round gasket inside the float bowl chamber with a rip in it. Could that be causing the bottom cylinder not to get fuel and therefore not firing? I did confirm I was getting spark by pulling that plug and resting against the block and started the engine and saw spark.
 
"Spes in the carb........." Black?

Hard to trouble shoot multiple cylinder engines on muffs. You didn't say the noticeable difference was worse, or removing 1 and 2 were worse and 3 had no effect.


On Fishinlight's comment, if the 60 is like the 75 through 125 hp 2002 engines there is no switch box....individual CDM/CDIs...forget which acronym applies....Capacitor Discharge Module probably as they are modules.....or CDI which could elude to the switchbox since they don't have the comprehensive modules and it is a Capacitor Discharge Ignition.
 
Texasmark, The specs were black and their was a noticeable difference when I pulled 1 and 2 but there wasn't a noticeable difference when I pulled 3. And Carb 3 was the one with the broken internal gasket.
 
fickesd1 said:
Texasmark, The specs were black and their was a noticeable difference when I pulled 1 and 2 but there wasn't a noticeable difference when I pulled 3. And Carb 3 was the one with the broken internal gasket.
Click to expand...

It looks like you pointed yourself in the right direction. New lines, new carb kit at least on #3. Might as well as do all 3 while you are doing it and will remove any black specks in 1 and 2. Ensure you remove the top plate on the carb (as that is where I found a lot of specks with mine) and clean that area out good too when you install your kits.

Brain "pfart": Just realized that my 90 engine had a top plate. Your carbs may not.....point here is remove anything that is removable when cleaning and remember the compressed air. A fine wire through the venturi tube never hurts either.....you can cut off a piece of electrical cord, remove the insulation and remove a strand..smaller the amperage the wire, the smaller the strand.
 
Last edited:
Back
Top