78 evinrude 115 idles and refs fine in driveway but on the water cuts out under load

misfit171 · Jul 22, 2013

My 78 115 will run great one night then the next it starts and idles no problem but when put into forward gear it goes 10 feet and dies . Sometimes it gets going okay then dies or runs rough. Sometimes it has trouble idling for a while ? I rebuilt the fuel pump and recently pulled the carbs they looked pretty clean haven't got to deep in cleaning them yet waiting to order rebuild kits . I think it's strange that the motor just stops immediately . No sputtering or anything . I have good compression but didn't check my spark plugs before taking the carbs off . Anyone with info will be much appreciated . I did run sea foam through it also??

Daviet · Jul 22, 2013

Re: 78 evinrude 115 idles and refs fine in driveway but on the water cuts out under l

I think you might be on the right track. Make sure and remove all the orifices and clean all the passages. Make sure the idle is set to the proper RPM with the engine in the water and in gear.

boobie · Jul 22, 2013

Re: 78 evinrude 115 idles and refs fine in driveway but on the water cuts out under l

What's your spark like when it just quits. Will it jump a 7/16" open air gap on a spark tester ??

emdsapmgr · Jul 23, 2013

Re: 78 evinrude 115 idles and refs fine in driveway but on the water cuts out under l

That engine will seem to run/idle just fine on the trailer when only running on 2-3 cyls. You need all 4 firing when the boat is under load in the lake. Follow boobie's suggestion. You can also check the spark on each plugwire with an inductive timing light when it's running.

misfit171 · Jul 23, 2013

Re: 78 evinrude 115 idles and refs fine in driveway but on the water cuts out under l

I have my carbs off the motor at the moment or I would check the spark . I have to order my carb kits and clean them up then ill be able to turn her over and check my spark. When I checked compression I looked at the plugs they seemed ok but will definitely test them for spark and a timing light soon as possible . Thanks for the replys it will be a bit before I get the carbs back on but ill update y'all when I do. Thanks

willy007 · Jul 23, 2013

Re: 78 evinrude 115 idles and refs fine in driveway but on the water cuts out under l

It couldn't hurt to check the fuel lines while you're at it. Old lines may be cracked or leaking resulting in a loss of fuel pressure causing your problem. I would agree with Daviet, you're on the right track but make sure that you take the time to do everything right so you're not back in the same position a year from now.

misfit171 · Jul 23, 2013

Re: 78 evinrude 115 idles and refs fine in driveway but on the water cuts out under l

Will definetly check the fuel lines . I'm also getting new plugs and a new water seperator filter . Thanks for all the help. Ill post my finds. Thanks.

fromcarsToboats · Jul 24, 2013

Re: 78 evinrude 115 idles and refs fine in driveway but on the water cuts out under l

I watched a guy complain about the same problems at the lake one day. Being the helpful guy I am stopped to help. Been stuck before it sucks. We went through everything we could while on the lake. it will run for a very short time then quit. I couldn't figure it out until i noticed the plastic fuel cell was being sucked flat. Opened the vent on the tank and it ran like a dream. Don't overlook the simple stuff.

misfit171 · Aug 1, 2013

Re: 78 evinrude 115 idles and refs fine in driveway but on the water cuts out under l

Okay got the carb kits put in new plugs rebuild for the fuel pump couple new hoses and intake gaskets . Did okay on the river tonight ran better than it had been , but I really think I need to sync the carbs but have no manual anyone have a way to do this without a manual? Thanks for all the replies and help much appreciated.

emdsapmgr · Aug 2, 2013

Re: 78 evinrude 115 idles and refs fine in driveway but on the water cuts out under l

A factory manual is the best reference for sync and link. It's got great pictures. Check out this website: outboardbooks.com

misfit171 · Aug 3, 2013

Re: 78 evinrude 115 idles and refs fine in driveway but on the water cuts out under l

I will thanks

78 evinrude 115 idles and refs fine in driveway but on the water cuts out under load

Seaman Apprentice

Fleet Admiral

Supreme Mariner

Supreme Mariner

Seaman Apprentice

Seaman

Seaman Apprentice

Seaman Apprentice

Seaman Apprentice

Supreme Mariner

Seaman Apprentice