Omc 5.7l not running right after head gasket change

[gdpalumbo]

Hello,
A little background, I purchased a Bayliner ciera with an omc outdrive and 5.7l engine. I knew the engine had overheated and a crankcase full of antifreeze proved it. I changed the head gaskets. Idled the boat in my yard for quite a while and everything seemed fine.
Took it out for the first time on the water and it idled fine but would backfire when under load bad. So while I was driving I had my brother turn the distributor and we got it to actually move without backfiring but anything above 3k rpms would give a bad pinging. Plus ....after turning the distributor the motor wouldn't start unless we put it back to where I set the timing. Motor is a reman and I talked to the reman guys and they said it's a 88-95 motor that's all I need to know when looking anything up.
So when I timed it, I timed it idling 2 degrees btdc as stated on the valve cover ....but, someone has replaced the stock distributor with a newer msd distributor and coil. Also they removed the stock (I think quadrajet right?) Carb and installed a 4 Barrell Holley double pumper. Pretty sure it's not a marine application carb. My question, I read something about grounding something on the ignition out for base timing is this correct with this distributor? Boat is an hour away and should be down to it this weekend hopefully. I watched a video about setting up the Holley carb and will try to make sure everything is adjusted correctly. My brother owned the boat prior and said it ran ok for him but seemed like it lacked power....I could not get the boat past 3k rpm even floored (with loud pinging I'm guessing was detonation) could someone point me.in the right direction? Also, heads were not resurfaced but we're checked with a head straight edge and a feeler guage and were perfect despite the previous overheating incident.
Compression is ok on all cylinders. Plugs are new. Wires are existing, cap and rotor are fairly new. Firing order I checked liked 10 times (and rearranged probably 4 times :facepalm.

 

[Scott Danforth]

by OK on the compression numbers, what were they?

regarding your carb.....pull the carb apart and go thru it. a Holley carb is easier to go thru than fixing a toilet

the backfiring was a lean sneaze (you are running lean)
the pinging is running leaner and that is your pistons eating themselves.

so stop running it until you fix the carb

OMC came with a variety of carbs, that includes Holley and Q-jets

marine carbs will have J-tube vents

a double pumper would be stock on a big block, not a small block

what actually came on your OMG would depend on year, etc.

if you have an automotive carb, look into a marine carb.

setting base timing depends on the distributor you have. you should be about 8 BTDC at 600 RPM and about 30 degrees BTDC at 3000 RPM

 

[gdpalumbo]

Compression numbers were all over 100 I can't remember off the top of my head I just remember checking and it was good, this was in early winter. I will check the carb for marine vs non. The guy did tell my brother he replaced the carb that was on there with a Holley so I will check into whether it's a marine carb and will verify the double pumper . I had a feeling it was running lean. I will stop running it until it is fixed. My brother just dropped off a q-jet to me that came from a 5.7l I might just try swapping that carb out. I have a feeling Holley is definitely a auto carb and who knows if the right Jets and power valves are in it. I know for sure the qjet was correct and running on a 5.7l because I pulled the motor it was on. I will keep you posted. Thanks for your reply I appreciate any help I can get.

 

[Lou C]

The OMCs came with Quadrajets until approx ‘89 and then changed to Holley in ‘90 if I recall right. The 4.3s used the 4160 with an adapter and the V8s used the spread bore 4175 without the adapter. Does the carb that’s on it have J tubes for the bowl vents and the fitting for the yellow overflow tube from the mechanical fuel pump? I would not use an auto carb on a marine engine; there are safety risks and it will probably be jetted to lean for marine performance.

 

[gdpalumbo]

Btw, is it true about grounding the lead out on the distributor for setting timing? It's an msd distributor

 

[Lou C]

PS I actually found the Quadrajet easier to take apart band rebuild than the Holley. I feel that the QJet if an un-modified marine unit in good shape it is the superior carb at least in my experience.

 

[Lou C]

Sorry can’t comment on the distributor. What are you doing to make sure the ESA works? Normally you need to use a different module with an electronic distributor.

 

[gdpalumbo]

The esa still works, I tested it and it still stalls the engine by pressing with my finger. One more question, the qjet carb I have cAme off a 5.0 is there anything that needs to be done to put it on a 5.7?

 

[gdpalumbo]

As far as I understand, all the esa does is ground out the ignition coil I don't know of any module

 

[gdpalumbo]

Yes the carb does have the j tubes

 

[Bt Doctur]

verify the plug firing order

 

[gdpalumbo]

Also, I did not verify firing order but would an engine really run up to 3k rpm with the wrong firing order ?

 

[gdpalumbo]

Ok, so I went down to the boat today. Installed the quadrajet I had. The Holley double pumper that was on there did not have a fitting for the overflow so it must have been an auto carb. I timed it to what you guys suggested and checked the timing at 3k Rpm underload and it was at the 30 degrees. It seems to run ok up to 3k Rpm maybe a bit rough but ok. I was getting 14mph out if it at that Rpm, I'm not sure what this boat should run at with the 1 5.7L. once I give it throttle to go past the 3k it starts to open up the other Barrell and it doesn't have any power to go past the first two barrels opening. It just starts to what sounds like ping (sounds like really noisy lifters?) And literally has no power even at full throttle past that . It just can't do it. Fuel pressure is ok there is a Guage on it. Always stays between 5 and 7 psi. I'm really stuck with this. If someone could point me in the right direction I've already paid to keep this boat down there. Next step is paying a mechanic but I really can't afford to do that so I'm trying to get it done myself. Also, it idles.and revs fine out of gear, actually sounds really good out of gear (but don't they all). Any input would be greatly appreciated. I didn't run it past the 3k for long because I know that sound isn't good.

 

[gdpalumbo]

Sorry to bombard with posts but is there any possible way this could be attributed to fuel being old? The person I bought the boat from put fuel in it late last summer/early fall and it's the same fuel in there now

 

[Lou C]

At 3000 rpm the boat should be fully on plane going about 30 mph. While the fuel pressure is ok I’d check the anti siphon valve on the gas tank fitting that the fuel line from the pump is hooked up to. It could be corroded and stuck restricting fuel flow.

 

[gdpalumbo]

Firing order is correct. Also removed fuel pickup from tank. I don't believe there is an anti siphon valve. Just looks like a block 90. I was able to blow into the tube and could hear it in carb. Didn't get a chance to take it out. Going to head down this weekend and try some fresh fuel I guess