merc spitt'n n spudderin'

[illMATTic]

i just ran my boat for the first time this past weekend. it was 84 here in MI. i have a merc 115. well when i run it wide open it will run great for about 20 sec. then it loses power. i then back off the throtle and floor it and it will act the same. i can run it all day at 3/4 throtle. is it fuel or spark. i havnt looked at either yet.

[illMATTic]

i just ran my boat for the first time this past weekend. it was 84 here in MI. i have a merc 115. well when i run it wide open it will run great for about 20 sec. then it loses power. i then back off the throtle and floor it and it will act the same. i can run it all day at 3/4 throtle. is it fuel or spark. i havnt looked at either yet.

[Chris]

My Mercs always acted that way when the stator was on the way out. Usually after the motor gets heated up the stator starts to act up. But it could be lots of things I suppose...

[175checkmate]

Check your fuel supply. When you are running take a look at the primmer bulb, is it hard, now run wide open. Does the bulb colapse? Mine was doing that, it was the fuel pump diaphram that went bad. Installed an electric pump. No more trouble.

[illMATTic]

how much does a stator usualy run? it ran good for the first 10 mins. then it started to cut out. the motor sat for about 4 years. never started for that long. then it was started and ran before i got it.

[jkeiper]

Have someone pump the primer bulb when it starts to bog. If it picks up and runs ok it is a fuel supply problem.

Regards,

Jim

[illMATTic]

whell when i prime it the bulb doesnt get too stiff at all. is this normal?

[F150GT]

If your fuel primer bulb is hard all the time it is probably old and the rubber is stiff, change it. Try loosening your fuel cap also, if the fuel tank vent is pluged you wont get enough fuel at wide open due to the vacume created in the tank while running. I cant help you on the Merc ignition, sorry.
F150

[illMATTic]

on a predictor, where would the vent on the tank be located?

[85Predictor]

http://checkmate-boats.com/6/ws/,s,8626072361/Graemlins/surf.gif
http://checkmate-boats.com/6/ws/,s,8626072361/Graemlins/offtopic.gif
My 115 didn't have enough power to plane.
Stator and 1 switch pack were bad.
Stator and switch pack ran a good
$200.00 each! (Ouch)

Hope your problem is something less expensive.
Nice looking Predictor!!
Mine is a 1985. Had some faded(milky) areas
on the bow. Ended up wet-sanding with 1500-2000 grit with alot of water(hose). Buffed out with Turtle Wax polishing compound then wax.

Good Luck and enjoy!!
Is the ice out yet??

[illMATTic]

yeah so i had the boat out. i can run it full if i pump the primer bulb now and then. would it be safe to say it is the fuel pump?

[illMATTic]

could it be the diaphragm? they are only like 5 bucks. just how does the pump work on a 78 merc?

[F150GT]

Sounds like the fuel pumps are getting weak,start by rebuilding them and test again.
F150GT

[illMATTic]

ok so i installed the fuel pump kit. it didnt do a thing. could the carbs need to be adjusted? could there be a vacume leak. when i pump the primer bulb it still works great.