Mercruiser: possible timing issue...Help

[slmdhs]

I have a 97 Starcraft it came with a Mercruiser 3.0. The 97 3.0 had a knock in it so i bought a new block (2012) and put all the accessories parts back on and dropped it in , also bought a brand new carburetor plugs wires all new filters and fluids.....the motor fires right up sounds great till you get to the water. It will not hold a load only idle speed. I have been told it was timing so i have 3 different mobile mechanics come to set the time but when i get back to the water still wont hold a load...I want to take it to a marina but i wanna know what I'm getting myself into first.

 

[achris]

Re: Mercruiser: possible timing issue...Help

The 3 litre came with several different ignition systems, which one do you have? The other thing to check it that it is advancing correctly with increase in engine speed. Also check for a vacuum leak. And make sure the exhaust system is clear.

I would also try putting the original carb on, and re-check, and then check again you have the plug wires on correctly. Not so common with a 4 banger, but V8s are notorious for sounding great even with a couple of plug wires crossed.

I'd also check the engine compression. Not unknown for a dodgy block to slip through....

Chris........

 

[Don S]

Re: Mercruiser: possible timing issue...Help

You need the serial number of your engine to be sure it's not a 96, not uncommon for boats to have a year older or even year newer engine than the year of the boat. The model year changes at different times.

Assuming you have a 96 or 97, you would have the EST ignition. Below is a file that covers setting the ignition timing on the EST. It's surprising how many marine shops/mobile mechanics don't understand how to properly set the timing on that ignition system.

View attachment 3.0 EST timing.pdf

 

[fat fanny]

Re: Mercruiser: possible timing issue...Help

Don is dead on! my 96 has a 95 power plant!

 

[slmdhs]

Re: Mercruiser: possible timing issue...Help

You need the serial number of your engine to be sure it's not a 96, not uncommon for boats to have a year older or even year newer engine than the year of the boat. The model year changes at different times.

Assuming you have a 96 or 97, you would have the EST ignition. Below is a file that covers setting the ignition timing on the EST. It's surprising how many marine shops/mobile mechanics don't understand how to properly set the timing on that ignition system.

View attachment 179422

the original motor was a 97 est the new one is supposed to be the same have to check for sure
the only thing i saw different is the mew block has a place for a knock sensor dont know if thats going to cause a problem.
the three mechanics that have been out have all said that they put it in base time with a jumper wire before you set the time.
Im going to check the fire order just in case i didn't do something right by the way this is my FIRST BOAT.
I starting to think something is wrong with the block but i sure hope not seeing as the warrant ran out 11 days ago.
would the firing order be the same on the 97 and 2012

 

[slmdhs]

Re: Mercruiser: possible timing issue...Help

the boat is a 97 24ft pontoon

 

[Don S]

Re: Mercruiser: possible timing issue...Help

You said you installed a new block, Since you used all the accessories off the old engine onto the new block that typically includes the ignition system.

Yes, they have the same firing order.

Was this a new Mercruiser long block, or _______________

 

[slmdhs]

Re: Mercruiser: possible timing issue...Help

You said you installed a new block, Since you used all the accessories off the old engine onto the new block that typically includes the ignition system.

Yes, they have the same firing order.

Was this a new Mercruiser long block, or _______________

yes it was new
yeah same ignition system but would the knock sensor make a difference

 

[slmdhs]

Re: Mercruiser: possible timing issue...Help

everything hooked up fine just had to change the flywheel

 

[Don S]

Re: Mercruiser: possible timing issue...Help

yes it was new
yeah same ignition system but would the knock sensor make a difference

3.0 engines and EST ignition systems do not have knock sensors. Post a picture of what you are looking at.