Ignition problems plzzz help!

Tha Dude

Recruit
Joined
Apr 25, 2011
Messages
3
seems I have a miss in my motor. the reason why I started looking it over is because:

Last week I was out on the water and the boat was running ok then all of a sudden it falls in rpm from 5000 to 4000 and will keep at 4000 for a while. it will run wide open ok but at idle will die. so I came home put my compression tester on it and came up with 120 psi on all four cylinders. then I put the timing light on it. at idle everything seemed fine after about 1700 rpm it seems like every cylinder fires every other revolution. my timing light will blink more often at lower rpm and less often at higher rpms. then while at about 4k rpm the motor will jerk a little and I hear a weird noise sounding like a little knock it does this constantly. please clue me in. and again every cylinder does this. also what is the degree of advance at idle and WOT if you know... thanks!


1996 112 SPL XE112SLEDR
 

gm280

Supreme Mariner
Joined
Jun 26, 2011
Messages
14,605
Re: Ignition problems plzzz help!

First of all welcome to iboats :welcome: Always great to have another boater aboard...

With just the info provided, I have to ask a few questions. When was the last time your carbs were removed and completely cleaned and new kits installed? And also when was the last time you checked and/or changed all the fuel lines and fuel pump and primer bulb? For an engine to drop rpms at WOT for seemingly no reason suggests a fuel delivery issue. It could be timing, but you stated that it runs great at idle or until you get to 1700 rpms. So when the carbs get to those openings you are starting to use the mid to high speed circuits in those carbs. Maybe a good cleaning and some carb kits installed would be a great place to start... JMHO though...
 

Watermann

Starmada Splash of the Year 2014
Joined
Jan 12, 2013
Messages
13,845
Re: Ignition problems plzzz help!

Great advice by gm280. You should also invest in a repair manual for your motor to get all of the specifics for it.
 
Top