NO REV UNDER LOAD

[scoop245]

2000 4.3 MERCRUISER I/O WON'T REV ABOVE 2200 RPM UNDER LOAD. had boat out monday ran perfectly fine. boat out tuesday and it won't rev under load above 2200 rpm. in neutral under no load revs fine. replaced carberator,fuel pump,fuel filter,gas,plugs,rotor,cap and checked timing after problem occured still no change. im thinking thunderbolt v ignition is not adjusting timiming. anybody have any ideas on how to check or any suggestions on what to do next?

 

[achris]

Hello and welcome aboard..

im thinking thunderbolt v ignition is not adjusting timiming. anybody have any ideas on how to check or any suggestions on what to do next?

Put a timing light on it and check? Also check that the purple/white base mode wire (for putting the engine into 'Base mode') isn't grounding somehow.

Chris.....

 

[scoop245]

update boat was timed at 8 degrees btdc using base mode. at 2200 "out of base mode timing is still only at 8 or 10 degerees. would this indicate a bad ignition modual?

 

[achris]

Start checking ground wires... The only thing that would stop the module advancing properly is a bad ground.

 

[scoop245]

not a bad module but just not a good ground?

 

[achris]

That's where is start..

 

[alldodge]

compression check

 

[nola mike]

update boat was timed at 8 degrees btdc using base mode. at 2200 "out of base mode timing is still only at 8 or 10 degerees. would this indicate a bad ignition modual?

Wait, you timed the engine to 8° while it was at 2200 rpm?