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View Full Version : 1986 (ish) Mercury 115 Cold Starting issues



weebo
05-24-2018, 12:05 PM
Hey everybody,

I have seen a couple of threads on here discussing this topic, but I wanted to throw my situation out there and get some feedback and helpful hints. My engine is really hit and miss... I have a habit of starting it before leaving the house to go to the lake. Sometimes, it is a very easy start, but usually it isn't. My engine has the "newer" style controls; I have found that I always have to max the throttle out and "choke" while cranking and usually have to squeeze the bulb back up a couple times during this process.

Once I get to the lake, I often have trouble getting it started again (beginning to think it is allergic to water). However, sometimes it will start right up.. But after anchoring out for several hours, I go to restart to depart and it usually gives me a fit, once again. Last night, I tried some of the tricks that I read about in these threads regarding holding the choke button in for 5-15 seconds and then continuing to hold while cranking. Each of these with no luck. I pulled the cowling off and popped the hose off of the enricher to ensure fuel was indeed flowing thru it, and it was. This is not a new issue, I have had this same problem for several years (every since I got the motor). Tonight I plan to try the trick of "fogging" the carburetor with a fuel/oil mixture in a spray bottle.

When operating the boat, it runs great! Awesome top end (approximately 25 MPH on a 24 Ft Tri-Toon) Starting is really the only issue, though it is a huge one. I seem to be getting plenty of fuel flow to the motor itself, along with fresh fuel, bulb gets hard when squeezed, 2 new (fully charged) 650 CA batteries, and spark going to all 6 cyls. I do plan to pick up new plugs today, but considering this has been an ongoing issue (even after previous plug changes) I don't anticipate much change there. Also, one other point, When attempting to start, the motor will "bump" one time as though it fired and then the starter disengages, followed by a "grunt" from the motor while spinning down. sometimes will disengage even without the "bump" mentioned earlier. I am hoping that you guys may be able to shed some light on some of these symptoms and provide suggestions, as I am at a loss.


Thanks in Advance!

Krazymaan
05-28-2018, 01:11 AM
Have you done the basics like open up the diaphragm fuel pump and remove the sand from the screen and check to make sure the diaphragm isn't all wrinkled up. Did you replace the fuel lines yet. Did you remove the factory brass fuel ends with new barbed ends that you can get from almost any hardware store. Maybe you have a carb issue if you have to floor it and choke it. That causes a larger vacuum to draw fuel in, as in maybe your idle circuit is partially plugged. You might need to open your carbs and clean the sand out and get one of those "tip cleaners" like for torches to run in and out of the jets and other tiny brass tubes.

Motv18
05-28-2018, 05:30 PM
if you’re using 91 e free then just have to live with it.

If if you can find heptane to lower the aki it helps.

Theirs other things to get to get the ole 5:1 and 6:1 to start esier but it involves messing with time and bump the compression.

DanUmbarger
05-31-2018, 11:03 PM
Sounds like you may have more than 1 issue. What is the main problem...starter/bendix disengages before it starts or motor cranks fine but won't start? You may have a bad starter/bendix to start with. Once you get the engine to turn over without kicking out then I would spray some fuel into one of the carbs to see if it is a fuel issue or a spark/ignition issue. If it starts spraying fuel in a carb then you have an enrichener problem...bad hose/plugged nipples on the intake side etc. If the engine runs fine after initial startup the your hoses etc are prolly fine. Take it slow.