1987 searay 5.7 eng posible misfire

[betayv]

1987 sea ray with a 5.7 engine, bought couple of months ago been doing a lot of maintenance on it, replaces spark plugs, distributor cap, rotor, set on correct timing, boat start on muff, and after engine warm, have a small misfire, when I replaced the cap I marked all the wires, I don't know if the wires were in the correct firing order, anybody have the firing order?, please advice, I didn't change the coil or the spark plug wires.

 

[Scott Danforth]

Chevrolet V8 firing order 1-8-4-3-6-5-7-2

 

[achris]

If the engine is also 1987, then the firing order is 1-8-4-3-6-5-7-2. If you have a pair of insulated pliers (or as I do, a HRC fuse puller) pull each lead off one at a time and see if you can isolate the problem to a particular cylinder....

Chris.......

 

[betayv]

my cap has some numbers in top of it like 3 under is a 5, 7 under a 4, what this means how I know from the spark plug what is one, eight, please advice

 

[Scott Danforth]

Ignore any numbers on the cap. pull all the wires off the cap, bring the motor up to TDC on the timing marks on your balancer and on the compression stroke of cylinder #1. then look under the cap, where ever your rotor tip is, this is cylinder #1. from there clockwise1-8-4-3-6-5-7-2

you can also google SBC firing order

 

[betayv]

ok guys replaced ignition coil, verify fire order and installed new spark plug wires, and still have the fail engine shaking a little bit, what else can I look, please advice.

 

[Scott Danforth]

when was the cap and wires replaced?

 

[betayv]

hi scott the cap and rotor was replaced this week and the wires and coil yesterday.

 

[achris]

Was it all running properly immediately prior to replacing parts, or were the parts replaced to try and fix the problem?

 

[betayv]

ok here is what I find out today one of the risers gasket was leaking water, I replaced the gasket and is running better but still failing, before replacing the cap and wires yes was failing too, one question guys is possible that gas is causing all this issue, the gauge is showing less of a quarter tank, and I smell a lot of gas on the carburetor.

 

[betayv]

rochester quadrojet issues

1987 Rochester quadrojet was rebuild by a local shop, 350 engine, boat run but smell a lot of gas, brand new plugs I pulled them out and they completely black, I try to adjust the mixture screws, but got worse even backfiring flames on one of the carburetor barrel, please help how can I fix this. advice thanks.

 

[achris]

ok... Problems before parts being replaced. Time to go back to basics and verify everything else is working correctly.

Standard troubleshooting for an engine.

Engines require certain things to operate properly... Basically they need the correct fuel/air mixture to be compressed and then fired at the right time.

So, in this order.

1. Compression and leakdown tests.
2. Check spark plugs, replace if needed.
3. If points, replace, along with condenser and rotor. Check and adjust, if needed, points cam dwell angle.
4. Inspect distributor cap, rotor and leads, replace if necessary.
5. Check spark quality (needs to be a nice BLUE spark drawn over 1/2").
6. Set timing. Check timing advance is working correctly.
7. Check/change fuel filters and check that the fuel system is not sucking air.
8. Check fuel pump pressure.
9. Check for full opening of the carb. Also ensure choke is opening fully when the engine is warm.

Chris.........

 

[achris]

Having read your other current thread, I would suggest you check everything else first (compressions, leakdown, timing, spark quality) before attacking the carb.

 

[alldodge]

Agree with Chris, at least run a compression test. Also have the flame arrestor off the carb and right after the engine is shut down look down the carb. If you see fuel dripping down the throat your needle seat or float level may need fixing/adjusting.

 

[Scott Danforth]

since it starts to mis-fire when its warm, I would lean towards the distributor module. the older VP modules are more than a new distributor

 

[betayv]

hello guys little upgrade here, check for leaks nothing, pull the plugs and find out all the plugs are black covered, clean them with gas and brake cleaner and a brush, start the boat and is running better what will cause the plugs been black? please advice

 

[achris]

Sooty black (dry) or oily black (wet)?

 

[Blue Mist 97]

I would have to agree with others responding to your thread. Don't waste your money and time just throwing parts at it and hoping that will fix your problem. The mod here has given you basics to check so make sure you do those things first. What is your engine timing right now? I think a SBC should be around 8* BTDC or close to that. As others said before, make sure you find TDC (that's on the compression stroke) and then pull your dist. cap and see where the rotor is pointing. It should be pointing somewhere close toward the #1 cylinder (mine points toward the #2 cylinder, but I set it that way). Replace the cap and make sure the #1 wire is in that spot closest to where the rotor was pointing and then clockwise install #8, #4, etc. In other words, make sure your wires are in the right order.

If all that is good and you still have problems, one or more of your wires may be bad. How old are the wires? If those are OEM type wires, they can break down pretty fast. It is not unusual to find a bad wire or two, especially after you pull them off to replace plugs.

I read your other post about Quadrajet, and will respond there.

Good Luck.

 

[Blue Mist 97]

Is this the original carb? If not, is it a marine carb? You said it was rebuilt by a local shop, so do they specialize in quadrajets?

Quadrajets are not that hard to rebuild. I rebuilt many of them in my younger years, but they can be a big problem if not done right. Most anyone can overhaul a quadrajet (or most any other carb), but not all that many can do it correctly.

Find a good racing carb shop and see if they can help you out. It will cost more, but it will probably be done right. Sorry, JMO.

 

[betayv]

hello guys the plugs are oily black.