1987 mercury 115 hp dies when put into gear

[cbalkarran]

I just purchase a 1987 mercury 115 hp 6 cyl. the problem is, when the motor starts is will idle and when put into gear it just dies and will take about 15-20 rest before it will restart. when i first bought the boat and motor. is work great on the test run on the water, but now its doesnt want to run.. any help is highly appreciated.

thanks
tony

 

[Ski'nBlind]

Re: 1987 mercury 115 hp dies when put into gear

Tony,
Really need more info about what's going on:

Do you smell gas or see gas floating on the water behind the motor?....meaning flooded or stuck float or maybe fuel pump.

Does the primer bulb or fuel line suck down flat when you can't get it re-started, does the primer bulb squeeze and stay hard?... meaning fuel starvation.

Can you hear the electric choke selenoid "click" when you turn the key to on and push in?

How old is the gas that was in the tank before you paid for the boat?

Have you checked for spark at each plug one at a time?

 

[cbalkarran]

Re: 1987 mercury 115 hp dies when put into gear

this is my verry first boat and engine, so i don't know a whole lot about the engine, dont know how to check compression etc...
the gas is about a month old it was fild up when i purchase the boat in order to test drive it.

the primer buld dosent suck down flat or stay hard

i typically give a half squeeze initallty to start the engine and that was working for it on dry doc with the garden hose hook up for cooling, even after i took it to the water it started right away initially, it started on the first 2 turns of the key and would stay running in neutal mode for more than 30 minutes,,, but after in cut off in the water it took about ~15minutes before it would restart and again would stay running as long as i dont put it in gear. and it did that about 6-7 time before i finally give up

did not see any significant amount of gas or oil in the water either...fumes for about 30 seconds and it goes away

yes i do hear the click on the choke when i turn the key and push it in.

thank you for you help in advance....

 

[arsenalpsu]

Re: 1987 mercury 115 hp dies when put into gear

What is your idle RPM IN THE WATER? It should be 800-1000max, i bet your?re around 500-700. When you put it into gear give it some gas right away, don't floor it just enough to increase the idle. It should stay running then. I'd recommend you do a link & sink. Search on here for the procedures. If you plan to do your own work on this go to e-bay or a local marina and by an OEM factory manual.

 

[cbalkarran]

Re: 1987 mercury 115 hp dies when put into gear

you are right arsenalpsu, the rpm is between 500-700 in idle but is dosent even give me a chance to giv it gas, soon i i try to shift it it just dies right away. but i will try wha you suggested will let you know...wont be able to get anything done till saturday, but will keep posting with results.
yes i do plan on doing my own work and i already have a factory manual. i wana learn as much as i can... thank you

 

[Mi duckdown]

Re: 1987 mercury 115 hp dies when put into gear

When you shift it, don't go easy. Sharp shift. Don't let it grind into gear.
Buying an OEM factory manual is a smart move.

 

[cbalkarran]

Re: 1987 mercury 115 hp dies when put into gear

thanks fellow boaters'' i will be trying all these suggestions this weekend while doing a tune up also.. will post results as i get them.

tony

 

[444]

Re: 1987 mercury 115 hp dies when put into gear

My 84 90hp 6cyl is kinda the same way. I don't have a working tach but just going by sound, I think the idle is set a little too low. If I start the motor up, then immediately put it into gear, it will stall. However if I first warm it up 30 seconds or so in neutral, it's fine and no stall issues all day. I agree with what was said above, when you put it into gear, quickly shove it into go to part throttle and it should not stall. Also with the primer bulb, you are supposed to be squeezing it until the primer bulb gets hard. Not just 1/2 a squeeze. If my hand ever touches the primer bulb, I squeeze the bulb until it gets firm.

 

[cbalkarran]

Re: 1987 mercury 115 hp dies when put into gear

I agree with you on the primer bulb, but 1/2 squeeze is all it take to get had and i dont have to pump it any more. i have been letting the engine idle for at 15-30 minutes before i even try to get it into gear.will be be working on it tomorrow will keep posting result..
\thanks for the tip and help.

 

[cbalkarran]

Re: 1987 mercury 115 hp dies when put into gear

a little bit of up date, did not have much time to work on it... here i go....

so i swapped out the bad power pack with a new one... same problem..
changed the oil out and used new gas, still having the same problem...

engine will runn and go into gear on dry doc with water flow hooked up. but when put in to a tub with little back pressure engine will die and not go into gear.

compression is good all cylinders well withing 10%.

rpm is also good. 1200 idle and ~4000 in gear on dry doc.


hopefully i can figure this out.

gonna try to rebuild the carb this weekend.

 

[cbalkarran]

Re: 1987 mercury 115 hp dies when put into gear

more update,,


found a couple of dry rotted wires all acracked and corroded connected to the stator and the 2 power packs.. so i pulled the flywheel and replaced the stator, had a new one on a spare engine., but that did not do much for the starting problem though.

also rebuild the carbs and change out the old feul... but till this day i am still getting a hard start. take a few cranks before it will start. but if i use some quick start fluid it will start right away.

any more suggestion would be great.

thanks
tony