Poor engine performance

rmoore

Cadet
Joined
Aug 20, 2001
Messages
16
I have a 1993 4.3lx liter engine with 144 hours on it. The problem just started about a month ago. The boat use to go onto plane very fast. Now it takes forever. I have also noted a drop in rpm's, Used to be 5500 now 4200. I've done a compession test and they all read around 185 psi. I have installed a new coil(accel), new cap, rotor,wires,plugs and new 4 bbl carb. But none of these helped. <br />Looking for idea's and sugestions.
 

Walter

Senior Chief Petty Officer
Joined
Jul 3, 2001
Messages
787
Re: Poor engine performance

To begin with, changing out that many parts is a very expensive way to troubleshoot what could be a relatively simple defect and it's also quite easy to "build in" other problems in the process. When I hear what you describe, one of the first things that comes to mind is fuel restriction. Something as silly as a plugged fuel filter can cause all kinds of symptoms from poor top end speed to rough idle and everything in between. You didn't mention that it was inspected/replaced, so I'm working on the assumption it wasn't. If not...GO THERE! Before you spend much more of your hard earned cash...be sure you've checked the easy things first. <br /><br />Good luck and keep us informed of your progress...<br /><br />Walt
 

clanton

Rear Admiral
Joined
Jul 9, 2001
Messages
4,876
Re: Poor engine performance

See other post this board timing, same engine.
 

Walter

Senior Chief Petty Officer
Joined
Jul 3, 2001
Messages
787
Re: Poor engine performance

I also failed to suggest you should insure that you're getting full throttle at your carb. In my field of expertise, improperly adjusted throttle cables are the source of many low power complaints!<br /><br />Walt
 

rmoore

Cadet
Joined
Aug 20, 2001
Messages
16
Re: Poor engine performance

Walter, thanks for the prompt message. I did change the the fuel filter also. I also checked to make sure the new carb is getting full throttle. Could it be the ignition module is not advancing the timing? Also, could i have caused a problem when replacing the coil with a non marine coil?<br />Thanks<br />ay
 

rmoore

Cadet
Joined
Aug 20, 2001
Messages
16
Re: Poor engine performance

Clanton<br />I'm not sure what you mean by see other post. I do think at this point in time that i do have a timing issue.<br />Thanks
 

clanton

Rear Admiral
Joined
Jul 9, 2001
Messages
4,876
Re: Poor engine performance

See timing advance problem by Wakemaster, about 20 posts down.
 
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