1995 Mercury 115 bumps and chirps

[richw46]

My 95 Merc 115 has been a good motor but it started acting up in the cold (43F) water yesterday. I was out on Tuesday, running up to 20-30 mph with no troubles. Took it out yesterday, Thursday, and started having problems. I made a run of about 5 minutes full throttle, got to a spot and started fishing, no issues. Fished for an hour.

Started the motor and went to another spot close-by, about 25 mph, no issues. Fished about a half hour.

Started the motor for another spot, at 40 mph, drove about 10 minutes and there was a bump and the alarm chirped. I thought I hit one of the many small logs in the water, stopped the boat but with the motor running. I started up again, got up on plane at about 35 mph, went about 100 yds and another bump and alarm chirp. I dropped to idle speed and went to the shore.

The low oil alarm is connected but I removed the magnet because it was giving me a constant alarm. (known issue with the magnet coming unglued from the float in the bottom of the reservoir. I'm running double oil right now.) It can't be the low oil alarm so I thought maybe it was starting to overheat. I fished for about an hour, started it up and turned to go down the lake. As soon as I got on plane, another bump and alarm chirp. I slowed to 25, ran about 5 minutes, went to 30 and was able to get back to the area I started out from. As I slowed down the motor died, alarm for about a second, and all the electronics went out. I cranked the motor and it started right away. Electronics were still out so I did a reset on the main breaker. All electronics came back. I fished a half hour then went back to the dock at 30 mph until idle zone, idled into the dock and pulled the boat out.

Another issue, the power trim was acting up. Motor would go down but going up was slower and slower until it wouldn't raise at all, but the trim motor would whine. Back home in the garage it worked OK but wouldn't go all the way up. I checked the fluid and it was a little low, needed about 2 tablespoons of ATF. Water temp was 43 but it was 42 2 days before.

I don't think the 2 issues are related. I've not experienced anything like the motor bumping then the alarm chirping before. It starts and runs fine, battery is 1 year old but I keep it on a 3 bank charger and timer in the garage. Battery connections are clean and tight.

Thoughts? Anything I can try the next time I go out?

Thanks,
Rich

 

[richw46]

The trim / tilt problem was due to low oil, the fill plug was leaking. I replaced the plug and refilled the reservoir / bled the cylinder. Now it raises and lowers without any hitches. I suspect that the bumping was due to the low oil and perhaps the suddenness of the bump was somehow triggering the alarm to chirp. I have not taken it out on the water because of the weather but hope to get it out maybe this week.

Two months ago I removed and cleaned the 4 carbs, they weren't very dirty but had never been cleaned. I got the Mercury gasket kits and replaced all of the gaskets too. I reinstalled and replaced the 2-stroke oil hose between the oil reservoir and pump. I didn't know there was a release button on the pump and wanted to make sure there was oil going to the motor. I mixed a couple gallons of gas with 2-stroke oil and added it to the tank, then drained the fuel hose until the fuel changed color. I pulled the kill switch and cranked the motor (water muffs on) until oil filled that new oil hose. I reset the kill switch and started the motor, sounded great. I have taken several trips since then without any problems. Water separator was replaced in 2017 (first time) with Teleflex separator. I also replaced the fuel line & squeeze bulb; Quicksilver product.

The stalling of the motor may be due to old gas and running double oil. The gas is from the summer and I didn't put any Sta-bil in it. Engine starts easily and idles fine. I have run at 25-45 with no issues (until this last trip) but once in a while, when throttling back as I arrive at my destination, the motor will stop. I can put it back in neutral and restart and it's OK again.

I'm going to drain the rest of the gas today an put in fresh 89 octane. Maybe I can get it on the water for a run.