mercury 1987 115 hard starting

[bass racker 87]

i have an 87 115 mercury hard time starting it but when it fires it acts like it is loaded up and will not rev up when in gear but in neutral it revs that happens for 20 mins. then runs like new. carbs are rebuilt . new plugs . any advise.

 

[Charlie61]

Re: mercury 1987 115 hard starting

you may not be firing on all 6 it may hot after 20 min, to run use a timing light to check spark

 

[Dick Bacon]

Re: mercury 1987 115 hard starting

I have a 1988 Merc. 70hp. Mine does the same thing. I just removed and cleaned all three carbs and installed new needles. I installed new plugs. I brought it into a local shop and had them replace a broken spark advance lever. They set the timing\syncronitation. Then it ran and started great a couple of times. Last time out, it started again. Hard start, runs weak at full throttle for 10 minutes, then takes off like a champ, runs great for the rest of the day. I'm at a loss too.

 

[Vision91]

Re: mercury 1987 115 hard starting

i had the same issue with mine as well and come to find out that the carb needle settings for the mixture was incorrect and the ignition coil gave out on me which was the main issueto begin with. im pretty sure someone on here will see this and out a portion of the manual for redoing the carbs...unfortantly i dont have one.

 

[hoosiercaver1]

Re: mercury 1987 115 hard starting

I have a 1970 115 that's hard to start after I anchor out and let it sit a couple hours. Starts pretty easy cold to unload it off the trailer and runs good till I park it. I ended up puttin a fresh set of plugs in cause they looked a little damp from all the cranking. Then with a little choke it finally started but stumbled under load and died until it warmed up about two minutes then I nursed it back to the dock. It seemed to run fine once it got goin tho, I just didn't want to risk havin another problem cause I had my wife and newborn on the boat. Once at the dock I shut the motor off so I could get the trailer. Then it wouldn't start again once I went to load it so I swam it to the trailer. I feel like its a fuel problem and it loosing it's prime, but I don't want to rule out an ignition problem either. Where should I start? I hope all of issues will help us trouble shoot the problems.

 

[Vision91]

Re: mercury 1987 115 hard starting

when you pump the bulb does it get hard and stay that way or does it loose its pressure after a few mins...when is the last time you cleaned the carbs and replace the diaghram in the fuel pump it could have a small hole in it mine did..id start with checkin all the fuel lines and also make sure the vent for the fuel tank isnt clogged that will give you a hard time with it cause these engines like fuel and lots of it..tearing the carbs apart is pretty simple you can do it within a couple hours and get a rebuild kit for the carbs and fuel pump...the kit for the fuel pump costs around 14 or 15 dollars and maybe 25 or 30 for the carbs.. but for hoosercaver1 see if the carbs are getting fuel if they are you can use carb cleaner but id prefer using a spray bottle of mixed fuel and spray it in the carbs and see if it will hit or start for a few secs if it does its the carbs or fuel pump if it doesnt get a spark tester and see if you are getting spark...if you aint it have the ignition coil checked. hope that helps somewhat since im still learning about these as well

 

[hoosiercaver1]

Re: mercury 1987 115 hard starting

Yeah, I know I need to do some troubleshooting. I do have a little issue with the primer bulb getting soft. It seems like if I prime it before I go to start it, once I crank for 15 sec. or so I have to go back and pump a few more times before the motor will start. I replaced the diaphragms and went through the carbs last year, so I think they r good. It could be a problem with the bulb it self. I'll keep plugging away and keep posting what I find. Good luck and thanks for the help .

 

[Vision91]

Re: mercury 1987 115 hard starting

ok the bulb will loose its pressure a little when cranking the beast over thats normal and you should feel it pusleating as the same time cranking.

 

[hoosiercaver1]

Re: mercury 1987 115 hard starting

Ok it doesn't go all the way soft just not as hard as it was. I really want to check the timing to see if it is correct, but I'm a little lost on how to do it. I do not have any type of degree markers on the flywheel like I've seen in other posts and don't see a fixed mark to line them up on anyway. I am fimiliar with the three dots on the flywheel and the notch on the distributor pulley, but I've read the write up on the timing and link and sync several times and dont understand how I know how far the timing advances with no gauge and mark to go by. Also, does it take a special marine timing light or will a normal automotive one work?

 

[Jlawsen]

Re: mercury 1987 115 hard starting

Bad rings or worn cylinder walls. Once it warms up and the pistons swell a little it'll run. Do a cold compression test and then warm it up and do a warm compression test.