Will not start

[LuckyPenny]

I have a 1977 Mercruiser 250 (5.7) carb'ed with Mallary YL series Distributer. No mater what I do she will not start. Nothing. New points, plug's, rotor and cap. Carb is set to spec's, batteries good, engine roll's fine, no water in oil. <br /><br />What next?

 

[tommays]

Re: Will not start

i havent followed your problem but if the engine has good compression and the disributer is in correctly ???? a bit trickey<br /><br />its eather no spark or no fuel with spark first at the correct time first on my list<br /><br />tommays

 

[cmyers_uk]

Re: Will not start

1) Have you checked the compression<br />2) Have you checked your getting a good spark. Turn the engine over in the dark to see if your getting any arcing.<br />3) Is fuel getting into the carb<br />4) Is the timing correct.<br /><br />What preceded the not starting? Was it running fine then stopped. Did you replace something then it stopped?

 

[LuckyPenny]

Re: Will not start

The previous owned had replaced the carb with an automotovive type, I replaced it with the correct marine carb. I did check the serial # and confirmed it to be mercruiser (marine) I replaced the cap, rotor, points, condenser and plugs.<br />As for the carb. I am getting gas. I checked in accelator pump and I am getting a good shot of fuel. <br />I just keep coming back to the ign. system.<br /><br />Right now I think the best thing to do is back up, regroup and start all over again.<br /><br />I did pull the distributer, and I am 99% sure that it was replaced correctly. My dwell is at 29.<br /><br />anything I overlooked?

 

[trog100]

Re: Will not start

it might sound a bit silly.. cos the question usually is "are u getting gas".. the assumption being that the problem is caused by not enough of the stuff..<br /><br />how about "are u getting too much gas".. <br /><br />the fuel air mixture does have to be within certain limits for it to be combustable.. a few too many pumps and an over affective choke could produce an over rich none combustable mixture right from the word go.. result an engine that will never start..<br /><br />have u tried starting it with the choke disconnected..??? or even the fuel supply shut of at the tank..<br /><br />again the last suggestion might sound daft.. but given some thought it isnt.. he he <br /><br />trog100

 

[Don S]

Re: Will not start

trog's right (ya don't hear me say that very often ) about it being flooded.<br />Pull the plugs out and see if they are wet.<br /><br />Does your engine backfire, pop, come or anything? Or just crank at the same speed?<br />Have you tried turning the distributor while cranking?

 

[trog100]

Re: Will not start

my "trogs right" count is about twice i recon Don..<br /><br />and coming from u i do take it as a compliment.. he he he.. <br /><br />trog100

 

[Haut Medoc]

Re: Will not start

If you are not getting any cylinder to fire at all, and your accelerator pump is delivering fuel, as you say it is, then I would say lack of spark or bad timing. Do you have any spark at all? Did it run before? Bad timing can be a broken timing chain/gear, but I wouldn't go there yet.

 

[rattana]

Re: Will not start

What is the voltage between the positive side of the coil and the engine block when the key is in the run position?<br />What is the voltage on the positive side of the coil and the engine block when the key is in the start position?

 

[LuckyPenny]

Re: Will not start

All of the help offered was good. and i found the problem, the distributer! the rotor; under the cap, was not turning or turning at a rate different than the engine. the outer shaft, which holds the the rotor, hense the octogon nut had sheered. since it was turning at a different rate I was not getting fire to the cyl yet the dwell meter would show a good dwell. Since all I could do was time it manually, there was no way to detect the problem with the light.<br /><br />I found the problem when I reached down to pull the rotor to check the dwell, and the entire assembly turned. My first thought was that the distributer was not connected to the cam, or one of the gears had stripped. The laugauge uttered would have made a sailor blush (opps, I am a sailor!)<br /><br />Has anyone ever run into this type of problem before? I checked with Mallory, the distributer based upon the S/N was original equipment (1977)

 

[Haut Medoc]

Re: Will not start

No, but I have a Mallory too and its older than yours {probably} 73 mine works fine, but thanks.

 

[LuckyPenny]

Re: Will not start

For Rattana:<br />in the run position the voltage is 12.5 (+/-) never looked in the start position. I suspect there is a voltage drop when the starter kicks in, I will check when I get the new parts. What should it be?