1988 Mariner 115 problems

[fishingwoodchuck]

Any help on this would be greatly appreciated.

Here's the low down.

-about 6 months ago, I did a carb kit on all 3 carbs
-I changed both fuel filters
-I use marine Stabil everytime I put gas in

Boat had been running great after the stuff mentioned above. While at the lake, I was on plane and running almost full power when it suddenly just bogged, or ran down like if I had pulled the throttle back. So I then pulled the throttle back and it would idle just fine. I throttle up again and it would plane out and run for about 30 sec then the same thing. It did this until it fouled the spark plugs. Take the boat home and

-Changed the plugs (Champion L76V), and the top 4 were dirtier than the bottom 2
-pulled the carbs and checked the floats and fuel bowls, all very clean and no particles or trash

Back at the lake again, boat ran fine to first couple of fishing spots then it started all over again, this time when it starts to bog or run down, I hit the choke a few times to see if it wasn't getting enough fuel, but no change. This continued till the plugs fouled again. I had some extra plugs and changed them (actually only had four, so changed the top 4). It would start and idle just fine. I limped back to the dock slightly above idle (took over an hour), and when I got close to the dock I gave it one more try and the same thing would happen. It would plane out, run about 20-30 sec then bog.

Thank You for any Input!

 

[ChrisfromVT]

Re: 1988 Mariner 115 problems

What's the status of the fuel pump? Try pumping the primer bulb when it bogs down. If this helps, your problem's likely a fuel pump needing a rebuild

 

[arsenalpsu]

Re: 1988 Mariner 115 problems

try the fuel pump, but go out again and bring a timing light. When she bogs down hook the light up and make sure you have spark on all cylinders, it could be your stator quits when it heats up. If you find you're missing spark start with the stator, then move to the trigger, then switch boxes.

 

[IronOutlaw]

Re: 1988 Mariner 115 problems

Check and make sure the choke isn't closing. My 55 Johnson did the same thing and it was my choke. It was weak and sucking closed at high rpms.

 

[fishingwoodchuck]

Re: 1988 Mariner 115 problems

thanks guys, I will check the fuel pump. I looked here on iboats for the fuel pump kit and I don't know which one to get. So how do I find out which kit is the right one and/or would it be better to get a new fuel pump? Also are these kits or new fuel pumps capable of handling ethanol? About the timing light, can I use one that I have for cars? I read a book about how to test the stators with a multimeter but will this still give me an accurate test or is it best to run it like you said for a more accurate test. The lake is a bit of a drive for me, so whatever I can do at home would work best but I am willing to take her back to the lake if need be. One last question about the stator, the book I have mentions that there are two stators, is this true?

 

[fishingwoodchuck]

Re: 1988 Mariner 115 problems

Iron Outlaw, how did you check the choke?

 

[IronOutlaw]

Re: 1988 Mariner 115 problems

Actually I'm not sure how to check it on a merc but my Johnson has a little linkage thing I tied open so that it could not close. I know they are different motors but they are very similar problems and could be the same thing.

 

[fishingwoodchuck]

Re: 1988 Mariner 115 problems

I will give that a try, Thanks Iron Outlaw.

 

[Dave1027]

Re: 1988 Mariner 115 problems

Hey Iron outlaw. Isn't your "tower of power" listed in you sig the same as the OP's motor?

 

[IronOutlaw]

Re: 1988 Mariner 115 problems

Yes it's an 86 mercury which should be the same as the mariner. I haven't messed with the choke on it though.