| Author |
Message |
    
Chris
Member
Username: 43_lx_merc_1996
Post Number: 65
Registered: 09-2006
| | Posted on Monday, June 29, 2009 - 01:26 pm: | 
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We were cruising at 2500, motor started sputtering & backfiring, then died. When we try to re-start it will fire but not run. For the past month it did have a noisy valve (I think).
Any ideas? Pull the head off?
Much appreciated! |
El Pescador
Senior Member
Username: el_pescador
Post Number: 4562
Registered: 02-2006
| | Posted on Monday, June 29, 2009 - 02:42 pm: |
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May its soul rest in peace (or is it in pieces???). 
Sorry, now seriously.
The simplest thing you can start doing is checking is the distributor has moved from its original position (maybe the clamp bolt is loose?). If OK, remove the cap and check its internal condition, as well as the rotor's, points, etc. If all OK, run a compression test and report back the results and we'll take it from there.
I hope this will be enough for you to start looking at some obvious causes. |
Chris
Member
Username: 43_lx_merc_1996
Post Number: 66
Registered: 09-2006
| | Posted on Monday, June 29, 2009 - 04:15 pm: |
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I will check that out tonight. Thanks! |
El Pescador
Senior Member
Username: el_pescador
Post Number: 4565
Registered: 02-2006
| | Posted on Monday, June 29, 2009 - 04:27 pm: |
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One more thing, make sure the choke is open. |
Robert A. Fierro
Advanced Member
Username: sandkicker
Post Number: 649
Registered: 06-2008
| | Posted on Monday, June 29, 2009 - 05:32 pm: |
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Check fuel filter for water. ( Remove carefully, pour out into glass jar...wait a few mins) |
Ricardo E.
Advanced Member
Username: ricardomarine_vp
Post Number: 353
Registered: 03-2009
| | Posted on Monday, June 29, 2009 - 11:21 pm: |
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I'm with the guys!
Use the good ole P of E.... (process of elimination).... one item only at a time until you either find a problem, and/or eliminate several possibilities. |
Robert A. Fierro
Advanced Member
Username: sandkicker
Post Number: 651
Registered: 06-2008
| | Posted on Tuesday, June 30, 2009 - 10:07 am: |
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Start with the cheap and easy items first. Too many folks immediately go for the big ticket item first. Very often its something really easy.
Spent many years in electronics... Rule number one..."Make sure it's plugged in!" |
Chris
Member
Username: 43_lx_merc_1996
Post Number: 67
Registered: 09-2006
| | Posted on Tuesday, June 30, 2009 - 12:49 pm: |
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Ok, here is what I found:
-No water in fuel
-Distributor tight
-Still loud rocker (Tick-tick) noise around #5 Cyl (see first post)?
-Engine still will not start.
Ideas? |
El Pescador
Senior Member
Username: el_pescador
Post Number: 4574
Registered: 02-2006
| | Posted on Tuesday, June 30, 2009 - 01:24 pm: |
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Try a compression test and report back the results. You may also want to remove the valve cover and have a look at the rockers in cyl #5. Further, you should remove the distributor cap and see how the distributor looks onside (rotor, points, etc). |
Chris
Member
Username: 43_lx_merc_1996
Post Number: 68
Registered: 09-2006
| | Posted on Friday, July 03, 2009 - 03:22 pm: |
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Unfortunately I can't get down to the boat for another week. Will get back with results ASAP. Thanks again for everyone's great help!
Chris |
Chris
Member
Username: 43_lx_merc_1996
Post Number: 69
Registered: 09-2006
| | Posted on Wednesday, July 08, 2009 - 01:03 am: |
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Finnaly got back to the boat today. The compression varied randomly from 135-150 on all cylinders. The rockers and distributor etc looked ok. Thoughts? |
Chris
Member
Username: 43_lx_merc_1996
Post Number: 72
Registered: 09-2006
| | Posted on Wednesday, July 15, 2009 - 01:42 am: |
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Will be back at the boat on Wednesday, any suggestions? See first and Jul 8th post.
Much appreciated, |
El Pescador
Senior Member
Username: el_pescador
Post Number: 4663
Registered: 02-2006
| | Posted on Wednesday, July 15, 2009 - 02:07 am: |
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The compression looks good. Make sure you have a flapper valve in the outdrive exhaust. If not, consider installing an exhaust bellows with a flapper valve.
Have you checked the ignition timing? |
Ricardo E.
Advanced Member
Username: ricardomarine_vp
Post Number: 397
Registered: 03-2009
| | Posted on Wednesday, July 15, 2009 - 09:25 am: |
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Nothing to do with your immediate issue, but keep your battery (s) charged up while doing all of this testing, etc.
Damage occurs to wet cell batteries when left in a state of discharge. Keep em topped off!
Chris, the only suggestion that I still have is to go through one item ONLY at a time and make sure all is working. P of E!
Fuel: Is the pump working? Filter good? Fuel tank pick up tube and the "screen" at the bottom clean? Anti-siphon valve good?
Carburetion: Carb working? Any water in fuel/carb? Have you removed/cleaned/replaced the Q-jet fuel screen?
Ignition: What color is your spark if you were to place a spark plug and wire directly into the coil and crank the engine over? (you want to see a whitish/bluish colored spark.... not yellow!)
With a VOM: Got power to coil? Purple wire circuit have power? What is the voltage here? Ballast resistor OK? Any questionable connections? Engine harness connection tight/good?
. |
Allen Cox
Member
Username: jaxworks
Post Number: 10
Registered: 04-2009
| | Posted on Thursday, July 16, 2009 - 11:59 pm: |
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Did the engine skip valve timing? Does it have a belt like the AQ125 series? |
Morten Ringvold
Senior Member
Username: haffiman37
Post Number: 3950
Registered: 04-2006
| | Posted on Friday, July 17, 2009 - 12:23 am: |
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Allen:
Sprocket wheels and chain!
Chris:
Bring along a timing light and multimeter and get the timing verified by cranking. In a case like this, You need 'solid evidence' and not just 'looks fine'.
Do You have 12 Volts from starter to coil when cranking?
Do You have 12 Volts into the ballast resistor with 'ign on' and about 9 Volts out of resistor to coil when 'ign on'?
Check by ohm meter that Your resistor in the rotor is not burned out. If possible replace points and cond. Use a dwell meter and not the points opening to set the points. That old distributor may give You headache. When changing the points take out the bottom plate in the dist and check for broken springs or stuck weights. |
Chris
Member
Username: 43_lx_merc_1996
Post Number: 74
Registered: 09-2006
| | Posted on Friday, July 17, 2009 - 05:54 pm: |
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Great! Thanks for the info. I'll try to get back to the boat next Tuesday. |
