Mercruiser 140 won't start

[rbruner]

Recently purchased a 1973 Silverline w/Mercruiser 140. I rebuilt the carb, installed a tuneup kit (rotor,condesor,points), replaced the fuel pump and fuel lines and adjusted the throttle as it would shut down when going into reverse. Motor seemed to run fine..started about 10 times and ran for about 15 minutes with no problems. Let it sit for 2 days and tried again and it wouldn't start. Checked the plugs and found they were fouled. Replaced them again and everything was fine. Went down to the river put the boat in the water, started her up and seemed to be doing ok. Got the boat off the trailer and it started to rev up so I shut it down and then when I went to start it, it wouldn't start back up. Now the plugs are fouled again and when i turn the key over the engine turns over and seems to run until I release the key and then it dies immediately. Is getting fuel just fine but I have not been working with boats long enough to know what to do past checking the things listed. Plan was to go boating this weekend, however my mechanic can't get to it till next monday after my only weekend off for a few weeks, so any help would be greatly appreciated. Thanks in advance.

Rob

 

[Don S]

Re: Mercruiser 140 won't start

Did you get the carb setup to specs when you rebuilt it? When you installed the tuneup kit, did you check and set the dwell, then the timing, and adjust the idle mixture and speed.
Did you do a compression test? Are the plug wires ok?

 

[rbruner]

Re: Mercruiser 140 won't start

I had help from a mechanic friend with the carb..i did set the dwell and adjusted the idle mixture and speed...i did not check the timing as the mechanic said it should be fine since i did get it running just fine...i also did not check the compression but was told that it was tested last year and was fine(probably not a good measurement) and once i got it running i did not think it was a problem till i got to the river and it didn't want to run....where can i find detailed instructions on checking the timing(i have a timing gun i borrowed). The plug wires look fine and were replaced last year as well by the guy i bought the boat from.

rob

 

[Bondo]

Re: Mercruiser 140 won't start

where can i find detailed instructions on checking the timing(i have a timing gun i borrowed).

Ayuh,.....

Here's the Manual for your motor,.....

 

[rbruner]

Re: Mercruiser 140 won't start

for some reason the link you gave is not working for me...and so far i have been unsuccessful at finding it on the mercruiser site or through google

 

[Don S]

Re: Mercruiser 140 won't start

The link works, but the file is over 1 GB (not MB) in size, I'ts huge. Even with a cable modem it will take a long time to download and save to your computer.

Check your timing, dwell changes causes timing changes. Your mechanic should know that ............... unless he is young and never dealt with points before.
What about the choke adjustment, and the idle mixture adjustments on the carb. The mixture adjustment should be done in the water with the engine running and warmed up.

Setting the timing is easy. Hook the timing light to #1 plug wire, shoot at the timing marks and line the timing mark on the pulley to the timing tab and turn the distributor till the right marks line up.