Slow plane

1sweet63

New Member
Aug 14, 2018
14
Boat Info
2002 sea ray 225 weekender
Engines
Mercruiser 5.0 efi
Hello everyone, hoping for some helpful info. I have a 2002 225 weekender w 5.0 mercruiser 5.0 efi I recently had water in the oil from a manifold gasket. Tore motor apart down to the heads. Cleaned replaced all gaskets, lifters manifolds, risers, plugs wires cap rotor and every other lil thing needed. Since then the boat was really slow getting to plane, as in like up to a minute or so. Once planed seemed to be running fine. I just adjusted the timing and it got better. My question is, the motor is running great at idle and wot no missing or sputtering but top speed is only 35mph and just doesn’t seem like it has the jump it should. Is this top speed normal and any ideas on why I’m not getting the jump out the hole I think it should? And yes I have it trimmed all the way down and it’s the same thing w low weight only 2 people on the boat.
 
Folks around here will want to know what size/pitch prop you're running. You could be running the wrong prop though generally you'd have either bad planing or low top speed, not generally both at the same time.

Do you keep the boat in the water or on a trailer/rack? Dirty bottoms can be quite impactful to speed/planing.
 
Was it was head gaskets or exhaust manifold caused water in the oil? How long was the engine run with water in the oil? You need to determine total spark advance of the ignition system. As asked what is the condition of the bottom and outdrive. What is the max rpm at wide open throttle?
 
Was it was head gaskets or exhaust manifold caused water in the oil? How long was the engine run with water in the oil? You need to determine total spark advance of the ignition system. As asked what is the condition of the bottom and outdrive. What is the max rpm at wide open throttle?
Was the manifold gasket, and it wasn’t ran very long w water in it. Block has been cleaned w marvels mystry oil and five oil changes. Rpms at wot is about 4000.
 
somethings not right...

how to spark plugs look? ...if they (all) look lean, clogged injectors?
compression test?
 
if you removed the distributor are you sure you did not install it a tooth or two off?.....you probably know this but with the #1 piston at TDC on the combustion stroke the rotor button in the distributor should be directly pointing to the #1 spark plug wire in the distributor cap.....

cliff
 
4000 rpms is a bit low. You may want to look for a new prop. You're looking for 4200-4600 rpms at WOT. A stainless prop would also work best.

The listed dry weight for your boat is 4525 lbs. Add 250-300 lbs. of fuel, 2-4 bodies and some gear and getting close to 5000 lbs. I wouldn't expect too much performance out of the little 5.0, it may be at it's max. That is why the 6.2L was offered as an option. Go down in pitch on a prop and go stainless. It might help a bit.
 
Weak fuel pump
It is a factory recommended fuel pump, I was under the impression they either wor
Folks around here will want to know what size/pitch prop you're running. You could be running the wrong prop though generally you'd have either bad planing or low top speed, not generally both at the same time.

Do you keep the boat in the water or on a trailer/rack? Dirty bottoms can be quite impactful to speed/planing.
the prop is the original, and didn't have a problem w it before working on the motor. Bottom is clean, fresh coat of bottom paint less than a year ago
 
if you removed the distributor are you sure you did not install it a tooth or two off?.....you probably know this but with the #1 piston at TDC on the combustion stroke the rotor button in the distributor should be directly pointing to the #1 spark plug wire in the distributor cap.....

cliff
Distributor is right. The first time we did the timing we did it as if it was a regular car motor set at dead nuts zero. Then through here i learned i needed to disengage the computer advance w a paper clip and set base timing. After we went about 6 over on the base timing, it was a vast improvement with it coming out the hole, but very little on top end speed. Because of that difference im thinking I can put more advancement on the base timing. Does anyone know the exact number I can advance it to? Cant seem to find that in the book? Also I was told I need to have the boat in gear and moving at 1200 rpms to set it, something about the shiftier telling something to the computer, is this true?
 
somethings not right...

how to spark plugs look? ...if they (all) look lean, clogged injectors?
compression test?
Compression good, plugs are new, also I feel if it was plugs or injectors, it would sputter or run rough, not smooth like it is.
 
Ignition timing can have a major affect on engine performance. Your 2002 engine would have an electronic advance. Most people set the "base" timing at idle and rely on the electronic spark advance system to get to the correct "total advance". The only ignition timing number that matters is "total advance". Setting total advance requires a digital advance timing light and some basic knowledge off how to use it. A small block GM engine should be set at no more than 32 degrees total advance at 3000 rpm. I'm sure Youtube has some good videos showing the procedure.
 
Ignition timing can have a major affect on engine performance. Your 2002 engine would have an electronic advance. Most people set the "base" timing at idle and rely on the electronic spark advance system to get to the correct "total advance". The only ignition timing number that matters is "total advance". Setting total advance requires a digital advance timing light and some basic knowledge off how to use it. A small block GM engine should be set at no more than 32 degrees total advance at 3000 rpm. I'm sure Youtube has some good videos showing the procedure.
So what exactly is the number the "base" timing should be set at on this motor?
 
Being a TBI are you using just base timing with the shift interupter wiring connected or do you use a scan tool to get into base mode?
What the fuel pump pressure?
 
Being a TBI are you using just base timing with the shift interupter wiring connected or do you use a scan tool to get into base mode?
What the fuel pump pressure?
Using a paper clip in the plug, which according to a forum on here does the same thing as a scan tool, put in the a and b holes grounds and disengages the computer advance timing. Not sure what the fuel pump pressure is, that beast is way under there and damn near gotta take out the motor to get to it, im not messing w it long as I know its working unless I absolutely have to
 
Using a paper clip in the plug, which according to a forum on here does the same thing as a scan tool, put in the a and b holes grounds and disengages the computer advance timing. Not sure what the fuel pump pressure is, that beast is way under there and damn near gotta take out the motor to get to it, im not messing w it long as I know its working unless I absolutely have to
And im sure the paper clip is doing something because the advancement is different with it not in there. But it may not be putting everything into base made if the tech is saying I need to do it w it in gear rather than bringing the rpms up w it in neutral
 

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