Mercury 115hp carb/power issues

darrelstuart

Recruit
Joined
Jul 25, 2010
Messages
2
Very frustrated in MN.
6 July 2009 I took my boat in because it was starting hard. Once it was started it ran fine. I was told a sync the carbs was what I needed. The beginning of my nightmare. It has never run right sense.From 6 Jul to 1 Oct they continued to work on the motor replacing part after part but never solving the problem. What happened was it now started ok but you put it in gear and give it juice it would wind uo slowley to top end and then bog down. If you thru the hammer, for a hole shot it bogged and died. They replaced ALL the electronics, switch boxes, harness,trigger, plugs etc. no change. The cards were rebuilt twice by them nothing fixed the problem. I had an oil/fuel blender on the boat, and they said that was the problem. It was removed and replaced with an automotive electric fuel pump! Still no power out of the hole. Frustrated because I lost the whole season and they wouldbn't give me my money back I stored it for the winter.

I took it to a new mechanic this spring. He said I didn't need all the stuff they did, it was in the carbs. The previous carb work was shotty. They put kits in, synced the carbs. Compression and leakdown were good, timimg was off, they reset it. Also replaced the water pump as it was weak and removed the electic pump.

It ran fine until we tried water skiing. Trying the hole shot with a skier and it bogged and died. It starts up fine but you can't get a hole shot to lift a skier out. You can feather it some and adventually it would pick up speed until you could be running full. Took it back they adjusted carbs and I tried it this weekend and it starts fine, idle fines, but no hole shot, it dies. You can't even feather it up to full power now. Any power more then idle or engaged it it dies.

I am very frustrated, I don't want another season to go by. This ran absolutely great June 2009 just started hard. Now Juky 2010 I have nothing.
Anybody got an idea???????????????

Darrel
 

Superjetjim

Petty Officer 1st Class
Joined
Jun 5, 2010
Messages
222
Re: Mercury 115hp carb/power issues

Darrell,

Have you tried a different tank? - Sometimes the pickup inside the tank can get blocked up by debris etc or the pickup pipe can kink as you hit it out of the hole restricting fuel flow if the pipe is a bit old/tired. Might be worth trying/borrowing an external 5 x gallon tank?

Jim
 

Bob_VT

Moderator & Unofficial iBoats Historian
Staff member
Joined
May 19, 2001
Messages
26,082
Re: Mercury 115hp carb/power issues

Welcome to iboats.

Merc carbs are very sensitive and if your carbs had gas in them when they were sored last year you probably have dirt in the carbs.

When you try to accelerate have someone squeeze the primer bulb...... you may have a weak fuel pump....in need of a rebuild kit.

Get a manual for the motor..... you will save $$ in the long run
 

nitro 39

Recruit
Joined
Jul 21, 2010
Messages
4
Re: Mercury 115hp carb/power issues

could be the top or btm mane barring im having the same trouble we skied last week it died an now wont get on plane booging pulled mine down top barring seems to be fine but side to side play in crank will thruogh one out of time
 

herb boughn

Cadet
Joined
Jul 23, 2010
Messages
20
Re: Mercury 115hp carb/power issues

Always check your mechanic first. Mercury will give them a certificate to work their products upon completion of basic lawn mower engine course. I know a guy who is now in charge of a Bass Pro Mercury service dept who put a new water pump on my engine when the problem was an ignition coil two years ago. Felony Stupid :p
 

darrelstuart

Recruit
Joined
Jul 25, 2010
Messages
2
Re: Mercury 115hp carb/power issues

Thanks for the info but, I tried your idea today and it didn't work. Still boggs and kills if you hit it.


Darrell,

Have you tried a different tank? - Sometimes the pickup inside the tank can get blocked up by debris etc or the pickup pipe can kink as you hit it out of the hole restricting fuel flow if the pipe is a bit old/tired. Might be worth trying/borrowing an external 5 x gallon tank?

Jim
 

arsenalpsu

Petty Officer 1st Class
Joined
Dec 1, 2008
Messages
290
Re: Mercury 115hp carb/power issues

Is this an i-6?? If so, you are running lean at WOT, that's why it dies during a hole shot. Seems to me your old mechanic messed up the timing, which the new guy fixed. (and screwed you out of $$$ for parts) What you need to do it move each carb's idle needel out (left) 1/8 turn, then try a hole shot. If it dies again, move each out again 1/8 turn. Keep doing this until you get no hesitation.

What you will notice is that this may make your idle a bit rough, but your hole shot will be good, this is normal and expected. Try it and report back!

PS- did the other mechanic give you your old parts back, if so PM me I may be interested in the switch box or coils....
 

Chris1956

Supreme Mariner
Joined
Mar 25, 2004
Messages
28,340
Re: Mercury 115hp carb/power issues

As for pulling a water skiier, your prop may have too much pitch for that use. If you have too much pitch on a prop, the motor will never get above fast idle.
 
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