Tuning Up 5.7L

[scarpint]

Re: Tuning Up 5.7L

OK..the tune-up saga continues for this newbie. Thought I'd share some things that may be of help to folks in a similar circumstance.

Here's the fuel inlet filter. I think it was in BAD shape. For giggles, I blew through the new one and then the old one and there was a clear difference in the amount of air that would go through it. Can't imagine what it would be like for fuel. Possibly a contributor to my stalling/rough running issues.



And here's what I poured out of the filter:



Well, getting the rotor off was everything it was advertised to be. I busted it up with vise grips and ended up cutting parts of it away with a Dremel tool. Real PIA but posters in this forum gave me the confidence to attack it. So, are we thinking this component should be replaced as well?

Thanks for considering!

 

[Scott Danforth]

Re: Tuning Up 5.7L

I would replace the pickup as well, when you have the distributor out to remove the broken screws. The crud in your fuel system indicates that the tank will need some attention as well.

 

[Wave thumper]

Re: Tuning Up 5.7L

You Wrote " I've owned the boat 10 years and have done nothing to the motor"

I was so surprised to read that. Has the boat been sitting there all that time or have you been using it for 10 years without a motor service?

That filter was totally full of gunk! I believe you may have a build up of that very fine silt in the fuel bowl of the carb.

 

[scarpint]

Re: Tuning Up 5.7L

You Wrote " I've owned the boat 10 years and have done nothing to the motor"

I was so surprised to read that. Has the boat been sitting there all that time or have you been using it for 10 years without a motor service?

That filter was totally full of gunk! I believe you may have a build up of that very fine silt in the fuel bowl of the carb.

The boat has sat the last two summers though it was properly winterized when I put it away. Prior to that, it ran really well for each of the years that we used it.

 

[scarpint]

Re: Tuning Up 5.7L

Guy at the Mercruiser parts desk says this unit is the correct Sensor Assemby for my 5.7L motor. Obviously it's different than the one above.

Is he correct? Is this an "updated" version of the assembly that requires some additional wiring to be connected during the install?

Thanks for considering,

 

[Scott Danforth]

Re: Tuning Up 5.7L

mercruiser buys sensors from both Mallory (Prestolite) and Cherry. both will work, both are fine, one requires an additional ground wire

 

[scarpint]

Re: Tuning Up 5.7L

Thought I would wrap this up. Got everything back together and motor still would not start. New plugs, wires, cap, rotor, sensor and fuel inlet filter. Would just crank and crank. Confirmed spark and started looking at fuel delivery. Removed fuel filter and it was full of fuel.

Replaced and cranked and cranked. Removed fuel filter again and not much gas. Removed supply line fom tank and put thumb over opening and had son turn key. There was suction. For giggles took air hose to fuel tank spicket and blew into supply hose to pump. Could hear air in carb.

Reconnected everything, cranked and it fired and died. Frustrated, I went WOT and it came to life and ran. Have started and ran it severall times since. Seems to run great in the driveway so far. I'm not familiar with fuel tank but there must be a filter of some sort in the tank that may have become clogged?

Thanks everyone who contributed to the thread! Will run it this weekend and see how it goes. Thanks again!

 

[NHGuy]

Re: Tuning Up 5.7L

I did my sensor this year and used one with studs and nuts on it, the new one was an exact bolt in. Maybe if you call the parts man he will swap you out to an exact copy. Can't hurt to ask.
If it's a superceded part requiring changes, there may be an instruction page in with the part, there usually is.

 

[scarpint]

Re: Tuning Up 5.7L

Ah, I am all set ith the sensor. It was an updated version that fit just fine. Came with instructions and since the motor is running now, I assumed I installed correctly. Rotor was the biggest PITA both removing and installing. Made sure to rotate the motor ensure rotor fins did not touch sensor per instructions. Easy to bend them installing.

 

[Glaspar_Fan]

Re: Tuning Up 5.7L

You do have an inline or water separating filter in the gas line along with the little carb filter, right? If not, install one now. Any old boat can have tons of crap in the tank. I remember the first time we went fishing in one of the tanks on our old Pearson. Nice monel tanks, but the senders had completely dissolved. Pulled out a few bits, but mostly had to just live with it. The inline filters of one sort or another are essential equipment.

John

 

[scarpint]

Re: Tuning Up 5.7L

Yes, there's the stock fuel filter/water seperator.

And ran the boat all weekend with very little trouble. It stalled a couple of times at idle but always restarted. Ran well at WOT. I did dump a can of Seafoam into it for good measure.