turns but wont start

[timmyt66]

just finished putting a new mercruiser 470 in the engine cranks but wont start i have no backfire through the carb its getting fuel and spark what am i missing ?

 

[surplusman]

Re: turns but wont start

timing if it cranks, has gas, and has spark, what else is there? check for proper distributor install or check the wires for correct order

 

[timmyt66]

Re: turns but wont start

thats all done already im at a loss

 

[blackz3]

Re: turns but wont start

wrong plugs ???

 

[timmyt66]

Re: turns but wont start

i wish it was that easy i have new plugs cap rotor wires i have spark and fuel the distributor was put in at #1 everything is there except fire

 

[Don S]

Re: turns but wont start

Where is it getting spark? If it's not at the spark plugs, then it won't start. Pull the plugs and ground the body of the plug, and with the spark plug wire attached, see if the plug is firing.<br />Check that you actually have gas and not water squirting into the throttle bores from the accelerator pump. Seen that happen several times, and water won't fire.<br />If you have compression, spark, and gas, it will fire.....may not run if the timing is way out, but it would at least backfire if out far enough or the plug wires are wrong.

 

[Don S]

Re: turns but wont start

One other thing, you said the distributor was put in on #1, but was it put in on #1 while on the compression stroke.....could very well be 180° out, but it would really backfire sputter and flames shoot out of the carb when 180 out.

 

[fireship1]

Re: turns but wont start

Hello, Tou said that you lined it up at #1. Were you at TDC? Could be that you are 180 out. I have done it myself and I have been fixing this stuff for a long time. Check it if you haven't already. Let us know how it turns out.

 

[fireship1]

Re: turns but wont start

Don was thinking in the same neiborhood I was. He beat me to the post!

 

[Bt Doctur]

Re: turns but wont start

gotta have voltage at the coil for it to fire.shift interupt shorting it out?

 

[timmyt66]

Re: turns but wont start

i will double check those things and let you know thanks

 

[surplusman]

Re: turns but wont start

I'll second that DonS. I spent all day trying to figure out why I had fuel, air, and fire but no run. Checked and rechecked the wires...all good. Finally figured out that I had the distibutor in 180 degrees out. What really mad me mad was I knew better.

 

[deputydawg]

Re: turns but wont start

I have had a few new engines that will spin, have proper gas, have proper timing and spark but still won't start. <br />Here is my solution every time. The cylinders are dry, causing a loss of compression. It will show good on a compression test but won't start.<br />Pull each plug out, dump a cup of oil in each, spin the engine to blow out excess oil. Replace the plugs and see how it works. <br />This will also reduce friction and save the engine a lot of wear.