Mercruiser 888 no go over 3000rpm

[Justboats1974]

Ok I have a Mercruiser 888 1974. I rebuilt the engine a few years ago. I checked compression..good on all cyc. New:
Edelbrock 1410
Summit street performer intake
Plugs & wires
Fuel pump, filter fuel pressure good..
Pertronics flame thrower II black cap distributor d230800. Coil pertronics flame thrower also.
In natural rpms good. Under load..won't go over 2750rpms, boat clean, prop new, 1.5 gearing on lower unit..what's the problem?

 

[Rick Stephens]

Welcome to iBoats Forum!

Recheck firing order.

1410 calibrated for your motor?

Float level checked?

What do plugs look like after running poorly?

Obviously with a good base motor we'll eventually figure out what's wrong.

Rick

 

[Justboats1974]

Welcome to iBoats Forum!

Recheck firing order.

1410 calibrated for your motor?

Float level checked?

What do plugs look like after running poorly?

Obviously with a good base motor we'll eventually figure out what's

 

[Justboats1974]

Checked firing order twice even ran motor on both firing orders..been running the Windsor firing order..haven't taken apart the brand new carb yet. Boats not running poorly..just not getting off it's ass. & plugs burning fine..clean burn..

 

[Scott06]

Are you getting full ignition advance . Assuming you have a mechanical advance, verify with timing light you are getting 28 or more degrees total advance by 2800-3000 rpm. Not sure of the specs for your engine but that is a rough ballpark

 

[Scott Danforth]

Checked firing order twice even ran motor on both firing orders..been running the Windsor firing order..haven't taken apart the brand new carb yet. Boats not running poorly..just not getting off it's ass. & plugs burning fine..clean burn..

Knowing which cam is in the motor is what determines firing order

Running the wrong firing order should be detectable with a cylinder drop test

What fuel pressure are you getting? Good doesnt tell us squat

What are the compression numbers? Good doesnt tell us didly

How did the motor run befor you bolted the other stuff on?

 

[kenny nunez]

If all of the above checks out then I vote for the fuel system as the cause.
Considering the age of the boat and fuel system‘s age take the 6 gallon outboard tank challenge. Connect it to the fuel filter inlet and give it a run.

 

[Bt Doctur]

might also be plug wires , cylinder balance will find it