2+0

i have a 2000 merc 115 4 cylinder but it will not kick in bottom two cylinders. what could cause this problem? it has spark in both cylnders after 18000 rpm.

Re: 2+0

sorry 1800 rpm could it be fuel problem

Re: 2+0

The 2 + 2 system should always have spark on all cyls.

The lower 2 carbs do not have complete idle circuits and do not pass enough fuel for combustion until the throttle is opened and motor speed raises to cause enough air flow to begin pulling fuel thru the main jet, around 1500 RPM.

An accelerator pump is used to provide a squirt of fuel to the lower cyls thru injectors mounted under the electrical plate on the starboard side of the motor as the throttle is being opened.

Disconnect the throttle cable with the motor OFF, disconnect the fuel hose from the accel pump to the injectors, watch the pump squirt as you open the throttle fully.

You may have to adjust the pump following the directions in the service manual, you may have to clean the injectors.

Check these links for a copy of your manual

http://forums.iboats.com/showthread.php?t=309079&p=2072211#post2072211

http://1manual.com/Mercury manuals/Service_Manual_Index.html

Re: 2+0

thank you charlieb i will try this tomorrow. these pdfs will be a big help.i will keep you posted.

Re: 2+0

well i finally got time to work on the motor. i cleaned out all fuel lines and fittings. i had to bleed the oil system but when i tried to bleed the outlet hose there was not any pressure the oil just dripped out, is that what it is suppose to do ? but the good news is, it ran a lot smoother while running on external tank. thanks for your help