Timing setting problem 5.7 help appreciated

[Welsh Rob]

Hi All
I have just purchased a Bayliner 2556 1992 fitted with a Mercruiser 5.7 that has the thunderbolt 1V ignition system.

Poor starting issues after putting the boat on its wet berth prompted me to change the following today

Plugs
Ignition leads
Distributor cap
Rotor arm

I also set the mixture as specified in the workshop manual,it is not the webber 4 barrel carb but the other 4 barrel one, I cannot remember if its actually a mercruiser item.

Anyway starting seems better from cold but still a little difficult from warm and I get the impression she will flood very easily!!??

I also went to set the the timing, again as specified in the book but here is my PROBLEM the timing pointer which is supposed to be spot welded to the timing chain cover had come away and was sitting in the bilge!

Other than pulling no1 plug and getting the tdc point are these motors ok to time by ear or is there another method I could use?

Many thanks in advance
Rob

 

[Don S]

Re: Timing setting problem 5.7 help appreciated

Not sure where you would find them in Wales, but in the US we can go to NAPA and get the "Pointer" as an aftermarket item that just bolts to the timing chain cover.

Here is what I am talking about.
http://www.sallee-chevrolet.com/frame.html?/Proform/timing_tab.html

 

[Welsh Rob]

ReUPDATE) Timing setting problem 5.7 help appreciated

ReUPDATE) Timing setting problem 5.7 help appreciated

Thanks Don,

I will investigate here in the UK,I also had trouble viewing the timing marks on the crankshaft pulley !

Could these have have worn away if just painted on or are they stamped in?

Final question are these motors prone to flooding with overenthusiastic throttle application during warm starts?

Thanks
Rob

 

[Welsh Rob]

Re: Timing setting problem 5.7 help appreciated

Don,Have sorced a pointer here in the UK and I'm told I should find a groove in the pulley at the tdc point.

So the only other questions are ......

Are these motors very timing sensitive i.e if not spot on they are a little lumpy on idle?

And the flooding question in my previous post?

Thanks
Rob

 

[Reel Poor]

Re: Timing setting problem 5.7 help appreciated

When setting the timming be sure it is correct (spot on). Also make sure the timming advance is working properly. Your manual should cover this also.

As for the flooding problem it would help to know which carb your motor has. It could ba a 2 barrel Mercarb, a 4 barrel Rochester, or a 4 barrel Weber.

 

[Welsh Rob]

Re: Timing setting problem 5.7 help appreciated

Thanks,the carb is a 4 barrel rochester.

 

[Bondo]

Re: Timing setting problem 5.7 help appreciated

"I also set the mixture as specified in the workshop manual,"

That's Only a Starting Point,...... Not the Final Setting.......

It Sounds like your Carb needs At Least a Rebuild,+ a Choke Adjustment.......
Possibly a Replacement........

 

[Welsh Rob]

Re: Timing setting problem 5.7 help appreciated

Thanks Bond-o

Have just placed an order for the carb refurb kit for my Rochester...........

Any tips or further advice on setting the correct mixture would be welcome...........

One point of note:-when I replaced the spark plugs last Sunday the old ones were very sooty and quite black indicating a rich mixture on checking the mixture screw it was off its seat by approx 4 full turns,manual states 2-3 turns...........

Setting by listening to the engine note while idling in gear (on water)at 650rpm its now at a shade under 3 turns off its seat.

Thanks to all so far
Rob