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Engine Failure this weekend

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I have a well maintained 1989 Mercury 115hp. This past weekend I headed out and for the first time had a little trouble getting it started. Once started, it idled fine and we hit the harbor on our way out to islands cuising at 18mph. Just past the last marker on the way out the engine lost power down to an idle then cut out completely. It would start up fine, idle for a few seconds then die. Checked all the fuel lines and the bulb, no obvious problems. Took off the fuel/water separator and it looked like it was full of iced tea. I took off the fuel line running into the separator and drained some gas into a bucket. Looked clean. Replaced the separator with a new one, primed the engine and it started up fine, idled fine so I moved the throttle forward and off we went. Unfortunately about a minute later it lost power again and then died. After that it would fire up okay but I could not get it running again. Got a tow in from some nice guys on the way in from fishing. Boat is now at my house but I have still not been able to get it running. Any ideas would be appreciated. Thanks.

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Most likely fuel contamination, fuel breakdown and clogged injectors, filters etc. Have you used stabil regularly? How old is the fuel? Can you hook up an auxiliary tank and change filters for another try to eliminate the obvious fuel issues? When you say fuel looks like tea, it points to ethanol/fuel related breakdown.

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Try starting while pumping the primer bulb. It sounds like a fuel issue but I doubt it's bad gas. Could be a bad fuel pump. If so, squeezing the bulb might help it run. If it does, either the pump is bad or there is a blockage in the fule delivery system. If there were a blockage in the tank ot tank pickup, the primer bulb would usually colapse so i don't thinhk that is the cause.

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if you have a 5gal portable merc tank try that with new gas dont forget to mix oil if needed, aslo follow the fuel line at the other end of the disconnect inside the motor theres a small round plastic black cap with a small screw in the middle of it inside that is a screen / filter remove it with care, theres a oring on the outside of screen the screen might be plugged you can clean it with a tooth brush re assemble/ they recommend you replace it with a new but this will be a start

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This has all the ear marks of an ethanol problem. Some of the issues are fiberglass gas tank? old unstabilized fuel? Lightly used engines have issues with ethanol. Old engines have a build up of gunk which ethanol desolves and moves into the engine. I've been in this situation and lost as 15yr old Yamaha engine 2yrs ago when ethanol was introduced. I hope this isn't your problem. Good luck JP

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first thing is to do a compression test, you definitely got some water in your gas, if it made it into the cylinders then you could have scored one, after that I would drain the carbs, the lines, the filter, tip the boat up as high as possible and pump off some gas to see if it still has water in it, might need to pull the catrbs apart and clean them out toob

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This could be three things: 1) It could be the fuel pump. If the diaphragm is worn and has holes in it, it may not be pushing enough fuel. Pull the line off the carb and try to start, BRIEFLY. See if there is a decent amount of gas coming out of the line. There should be a fair amount of pressure. It may be a good idea to run a small hose from the end of the line to a bucket on the ground, as you don't want gas to shoot all over the engine. If there is little or no gas, the problem is the fuel pump. Replace accordingly.

 

2) Fouled spark plugs. If there is significant build-up or carbonization, the plugs may not be firing properly, or not at all. Remove, clean, gap, and replace to check. If they are severely fouled, replace accordingly.

 

3) Carburetor is not functioning properly. The jets could be blocked, causing fuel to not be mixed properly. Or the fuel inlet valve may not be functioning properly, and not allowing fuel into the carburetor. (If you have electronic fuel injection, there is no carburetor. Remove the individual injectors and check for blockages. Replace if damaged, cracked, or stuck. Once you replace the injectors, clean the throttle bocy with Gumout spray)

 

If one of these three things doesn't work, do a compression test. You may have a more serious problem.

 

I see that there is suggestion in this thread of the possibility of bad fuel. While this is a possiblity, bad fuel will cause the engine to run erraticly, and can clog the carb or injectors. As fuel breaks down, it creates crystals. However, there is a distinct odor of vinyl. If your gas smells like new rubber gloves, replace the fuel and clean the tank. Clean the fuel system, as these crystals can damage the fuel pump and carb. This sounds more like a mechanical problem than a fuel quality problem.

 

Good luck!

Pricey doesn't mean better, but cheap is to the bone!

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Thanks for all the replies. I've got the morning off so I'm going to see if I can figure this out. I did replace the plugs yesterday and the fuel / water separator has been changed. I went out this morning and took it off to see if it looked like iced tea like the gas in the old one but it looked and smelled like gas is supposed to. The boat was used a couple of times a week up until the last month. It's been sitting for the last three weeks until this weekend and the tank was pretty low. I did put stabil in when I filled up the tank (52gal) at the end of August. Ran it 3 or 4 times unitl the middle of Sept then parked it until this past Saturday. Gas was low so I put in about 10gal of fresh gas and hit the water. You know the rest. I'll let you know what I find.

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Before going through a long process of eliminating issues do a compression test first, its the fastest and least labor intensive to let you know if the head is shot, if not, then proceed to trouble shoot. 1989 115 Mariner is the tower of power correct? Inline 6 engine (99.9% sure). If she needs a rebuild I know a guy in South Carolina that travels. Rebuilt my 87 115 inline for 1,200 (that was including the hotel room that he stayed in with his wife and food for 2 days). Guy is unreal.

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that price is awesome Parrot, I work at a marina that rebuilds outboards and we get $600 per cylinder, not sure exactly what he did for $1200 but that sounds like a hell of a deal if it worked out well for you, I hope things work out for you Tumbleweed and it's just a bad pump or clogged carbs

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You said that the fuel in the seperator looked like ice tea. That is a combination of water along with residue varnish from inside the tank. From haveing the tank low and then adding fresh to it. It stirred the stuff up on the bottom of the tank. To the point your pickup tube got into it. Like someone on here suggested. Tilt the boat and let it sit for a day or two so the stuff will settle to the lowest point. Then siphon it and remove the bad stuff. Seeing it went trough your fuel line. The carbs might need to be cleaned out.
SOL # 596
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