mercruiser timing

[brodie123]

Hi All;

i just rebuilt a 165hp Mercruiser I/O - new crank/cam/pistons etc - done by a pro shop

I think the carb needs a rebuild - lacking HP on top end and bogs under fast throttle up

the issue is timing - I bought an adjustable timing light from princess auto - set to 6 degrees and she starts well but lacks HP - problem is corrected by going up on the timing

question: what is a safe higher timing or is 6 degrees a must?

why would the higher advance give more hp?

fyi: electronic ignition

any adivce?

 

[Scaaty]

Re: mercruiser timing

You posted in the Outboard Forum...I'll contact a Mod, and move it to the I/O Forum

 

[Don S]

Re: mercruiser timing

Is this a 6 cylinder or 4 cylinder engine?

 

[brodie123]

Re: mercruiser timing

thanks for moving the post - brand new to the site

It's an inline 6

 

[Fishermark]

Re: mercruiser timing

Check the advance weights under the plate in your distributor and see if they are binding.

 

[Bondo]

Re: mercruiser timing

Ayuh,.....

While you Can advance the timing above the 6?,......
If you Do,.....
You risk Smoking your Brand New Motor......

Fix the Carb.....

 

[brodie123]

Re: mercruiser timing

Thanks. I had the carb rebuilt - still lacks top end. Had the intake manifold press tested and found a crack. :-( Can't find a replacement :-((

A good welding company said they should be able to fix it - is this a good idea?

Any suggestions on where to buy?

Would a small leak from water to exhaust cause a top end power problem like I am having?

thanks!!!!

 

[brodie123]

Re: mercruiser timing

I found a manifold - but it's a 2 barrel not a 4. I have a 2 barrel rochester on the boat now - it uses a plate as an adapter.

Am I safe to go with this other manifold?

 

[JCF350]

Re: mercruiser timing

As long as the carb is marine your safe.