Mechanic Help-Starting GM 225 5.7L

Mahoney

Chief Petty Officer
Joined
Aug 2, 2004
Messages
537
Recieved old boat not stored properly and water got in the carb and sat in the intake valve channels.<br />What I did.<br />1.Siphened out standing water from carb and intake valve channels.<br />2.Dissasembled carb and cleaned<br />3.Cleaned valve channels with wd-40 and air compresser, look fine now<br />4.Cleaned intake valve manifold, replaced gasket<br />5.Tested old gas in 50 gallon tank(30 gallons left) still seemes ok.<br />6.Replaced plugs and gave attempt at a rough timing.<br />Problems now.<br />1.Not sure if carb is adjusted properly after reassembling and installing.<br />2.When engine cranks I occasionaly get a few pops coming through the carb and periodically seems like a cylinder or 2 is firing correctly.<br />3.Engine turns very slowly when pushing trottle to get a bit more gas(this is when most of the actual firing happens,nothing happens when you dont give it a bunch of gas with the throttle.<br />Issues/Questions<br />1.I would like to start with some creative troubleshooting before replacing engine or expensive carb(maybe the starter needs to be replaced?)<br />2.plugs look wet and oily from carbon after turning, indicating probable flooding in the compustion chambers?<br /><br />What suggestions do you have for me to get this puppy rolling again?<br /><br />THANKS,<br />Shawn
 

WSUDERMAN

Petty Officer 2nd Class
Joined
Sep 9, 2001
Messages
176
Re: Mechanic Help-Starting GM 225 5.7L

Did you remove and re-install the distributor during this process? If so, the timing could be 180 deg. off or excessive initial timing. This will cause the engine to fire prior to the intake valve closing = back fire through the carb. And excessive initial timing can cause the hard cranking you mentioned. <br /><br />One other thought, If the intake was full of water, up to the carb, the valve seats might be rusted and be held open by the rust. A compression check would reveal this. If this was the case you have some major issues with the internal parts of this engine and a complete rebuild is an order...
 

Blk-n-Blu

Master Chief Petty Officer
Joined
May 12, 2004
Messages
821
Re: Mechanic Help-Starting GM 225 5.7L

What is the engine/drive<br />Merc or OMC?? 2 or 4 barrell carb?
 

Wart T

Petty Officer 2nd Class
Joined
Aug 1, 2004
Messages
102
Re: Mechanic Help-Starting GM 225 5.7L

firing order or timing is off.
 

Mahoney

Chief Petty Officer
Joined
Aug 2, 2004
Messages
537
Re: Mechanic Help-Starting GM 225 5.7L

Timing could be an issue, I initially had the timing 180 degrees off, and changed it, but it is very dificult to set the timing with the light when the starter is cranking the engine. I will repaint the timing stipe and try that again. I did check that the valves were opening and closing and they do seem fine, cranking engine over slowly with valve covers off indicated that the valves were all operating properly.<br />Any suggestions on the initial carb settings? it is a rochester quadrajet. I am unsure on what to set the initial idle screws to.
 

Mahoney

Chief Petty Officer
Joined
Aug 2, 2004
Messages
537
Re: Mechanic Help-Starting GM 225 5.7L

Oh, engine is 225 OMC GM sterndrive 1975is vintage
 

rattana

Chief Petty Officer
Joined
Jun 12, 2003
Messages
413
Re: Mechanic Help-Starting GM 225 5.7L

If it has points, give them a light cleanup with sandpaper. Replace them ASAP & check the gap is .020"
 

Mahoney

Chief Petty Officer
Joined
Aug 2, 2004
Messages
537
Re: Mechanic Help-Starting GM 225 5.7L

Points are clean, but worn, I should prolly replace the cap, however the spark is getting to the engine says the timing light. Gap is set to spec per manual at .035. I have the idle screws for the carb backed out about 3 turns or so, and was reading initial should only be about 1-1-1/2. I will monkey with that too and see if that does it. Boat was running like a top before storage, so I am pretty sure it will fire up once I find out what the problem is. Timing/mixture, or otherwise.
 

rattana

Chief Petty Officer
Joined
Jun 12, 2003
Messages
413
Re: Mechanic Help-Starting GM 225 5.7L

Plug gap .035" Point gap .016-.019" I think OBFG is right, the timing or firing order is out.
 

Mahoney

Chief Petty Officer
Joined
Aug 2, 2004
Messages
537
Re: Mechanic Help-Starting GM 225 5.7L

Sounds like it. I got the point gap set too with the feeler gauge. Ill continue to monkey with timing after readjusting those initial idle mixture screws.<br /><br />Thanks For all the help
 
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