GM 5.7 casting number
 

I had my engine replaced last summer have had issues since they did it. Yesterday I was removing the spark plugs to fog the cylinders and noticed all the plugs had the same look except for one. It almost looked new. It was dry and almost clean. I found the casting number on the block and looked it up online and it said it was a 95-00 engine. The casting number is 10243880. Does that mean I got a remanufactured motor or can you still buy a motor new with this casting number? Where can I find the serial number on this engine. The dealer told me it came from PCM in Orlando, Florida when I bought it and told me I would be getting a new engine.

I would ask this of an engine supplier, another boat dealer or even GM Marine division directly for that matter.

That is the "880 Block", it was and is still used for the ZZ4 crate engine and many other engine packages that are sold as "crate motors", i.e. sold without a chassis. I would wager that you could walk into any GM Dealership with a performance parts counter and look at the ZZ4 crate motor that they have on the floor and it will be an "880 Block" and be entirely new.

This block has the Vortec architecture and is generally setup for a roller cam. I would absolutely guess that PCM uses this block in either short block or long block form. I have this engine in my old hoopty '77 Corvette.

You say that one spark plug was dry, what where the others like? How about pictures of them? You may have either a fuel issue or an electrical issue. What problems are you having.

plugs
 

I will pul the plugs back out sometime this week and take pics.

did they install new exhaust manifolds??if not they could be cracked as well and be bleeding back into the cylinders causing a hydraulic condition making the boat hard to start............H

What are the issues and what make/model engine (assume its a PCM model) we are talking about as there is nothing you have told us so re the issues/faults at the mo so alot of guess work and conjecture here so far.

issues
 

The boat is a 2003 supra launch ssv with the 5.7 325 indmar assault engine TBI. Last summer I had a crackde cylinder so the dealer put in a new base 5.7 engine from PCM using all of my existing accessories. I had other dealers also tell me that part was fine. The issues Im having is it hesitates when it starts. It will be at like 300-400rpm and then go up to around 600 where it should be. Then when driving slow or coming off a plane into neutral the rpms will drop way down to around 200-300 and sometimes even stall. This is not everytime the rpms drops. I would say about every 5 out of 10 times going to neutral. The dealer tried to tell me indmar said this was normal. It never did this before they replaced the engine. I actually have an email from indmar telling me this is normal. SInce when is your rpms dropping and boat stalling out normal? Im about to the point where I am going to post the name of the dealer and workers and also the person from indmar that sent this email. This is getting old.

You don't have a fuel delivery problem, at least based on the fact that you have TBI. I originally thought maybe you had a bad injector since that one plug was dry, but that can't be since you have TBI.

My next guess is that you have an electrical problem. Do you know for sure if that cylinder is getting spark all the time? Has anyone check your distributor out? Timing? Advance? Firing Order? All those things can easily be screwed up by someone who just transfers parts from one motor to the next. What about a vacuum leak?

What about a vacuum leak?

That would be my second guess after the harness plug or ignition problem.

you have an MPI motor, not a TBI motor

so yes one injector can be bad

mpi
 

It is a TBI not a MPI. There are 2 injectors on top of the throttle body.

Did the dry plug come from the same cylinder number as the original cracked cylinder by any chance?

My guess is bad injectors and or fuel pressure issue. As far as that dry and clean plug, if the cylinder isn't firing, that plug would be anything but dry and clean. Post some detailed pics of the plugs if you can.

plugs
 

It did not come from the same cylinder that had the problem. I am off for 5 days so I will get pics up before the end of teh week. Thanks for all the help. I dont think it would be the injectors since there is only 2 on top of the tbi. If that was the case more than 1 plug would look like that wouldnt it?

Ignition problem would be a wet plug. But, plugs should never be wet, so to me, it sounds like 1 of 8 are good and the 7 wet ones are the problem.

A "dry" plug is either no fuel or not enough. Vacuum leak in the intake gasket right at the cylinder's intake runner or a vacuum port along that runner. Being that's its TBI, I dont suspect a fuel delivery issue.

funny because indmar sates that motor is MPI

i would pop off the flame arrestor and watch the injectors

if one injector stops at around 2000-2300 rpm, either you have a bad coolant sensor or bad oil pressure sensor

i would do a leakdown test

Engine on the Indmar website is the 2011 version that is 340hp NOT an 2003 that is 325hp obviously one of the things changed over the last 8 years is the injection system on this model of engine. Will be interested to see pictures when you get back BUT run the engine up first before pulling "dry plug" to confirm that the fuel just hasn't evaporated off it therefore leaving it dry.

Had a TBI engine doing the same thing as far as the low idleing and stalling and it was bad injectors.