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Evinrude 50hp 72 model won't start

S

Swirby

New member
Hi guys. I have recently bought my first boat. It is a 72 model 50hp motor ser 502020. It was running great but when out on the water it lost all power and at full throttle was only just crawing along. It then stalled all together and I couldn't get it started again. Once we opened the cover to notice a strong fuel smell and the two brass screws on the carbi had come loose and were falling out. I have put them back in and turned them 1 1/2 turns out. Also tried 2 turns and 3 turns etc. But can't get it to start. It seems to want to start but I can't tell if a spark is getting through. Or I the carbi needs tuning or where to start. Please help. Fuel seems to be getting through ok though. I did remove the spark plugs which were dirty so I cleaned them and put them back bit still no go.

Any my advise is appreciated as I want to et it going again ASAP. Thanks
 
Further it has all new fuel lines and electrics from battery through to engine. New water pump and spark plugs also just recently installed. These were all installed just prior to going in the water the first time. It seems the engine wants to start and all the right parts are moving starter flywheel etc but just won't kick over. Fuel seems to be coming through to the carbi too but just doesn't seem to want to fire off start.
 
The setting of the carburetor slow speed needle valves are somewhat critical... a little forgiving but a 1/3 turn out of the way will prevent the engine from running properly.

You need to purchase a couple RED nylon retainers, part number 315232 which will keep those needle valves from turning due to vibration. Seat them in the carburetor slot, then insert the needle valves. Adjust as follows. If this doesn't correct your problem, get back to us.

(Carburetor Adjustment - Single S/S Adjustable Needle Valve)
(J. Reeves)

Initial setting is: Slow speed = seat gently, then open 1-1/2 turns.

Start engine and set the rpms to where it just stays running. In segments of 1/8 turns, start to turn the S/S needle valve in. Wait a few seconds for the engine to respond. As you turn the valve in, the rpms will increase. Lower the rpms again to where the engine will just stay running.

Eventually you'll hit the point where the engine wants to die out or it will spit back (sounds like a mild backfire). At that point, back out the valve 1/4 turn. Within that 1/4 turn, you'll find the smoothest slow speed setting.

Note 1: As a final double check setting of the slow speed valve(s), if the engine has more than one carburetor, do not attempt to gradually adjust all of the valves/carburetors at the same time. Do one at a time until you hit the above response (die out or spit back), then go on to the next valve/carburetor. It may be necessary to back out "all" of the slow speed adjustable needle valves 1/8 turn before doing this final adjustment due to the fact that one of the valves might be initially set ever so slightly lean.

Note 2: If the engine should be a three (3) cylinder engine with three (3) carburetors, start the adjustment sequence with the center carburetor.

When you have finished the above adjustment, you will have no reason to move them again unless the carburetor fouls/gums up from sitting, in which case you would be required to remove, clean, and rebuild the carburetor anyway.
Thousands of parts in my remaining stock. Not able to list them all. Let me know what you need and I'll look it up for you. Visit my eBay auction at:

http://shop.ebay.com/Joe_OMC32/m.html?_dmd=1&_ipg=50&_sop=12&_rdc=1

 
Thanks heaps Joe. I will source the red plugs when the shops open tomorrow and give below a go. Today I am going to remove the carbis (x2) and give them a clean. This should put it in the best position not to have to be cleaned again a short time later.


QUOTE=joereeves;479258]The setting of the carburetor slow speed needle valves are somewhat critical... a little forgiving but a 1/3 turn out of the way will prevent the engine from running properly.

You need to purchase a couple RED nylon retainers, part number 315232 which will keep those needle valves from turning due to vibration. Seat them in the carburetor slot, then insert the needle valves. Adjust as follows. If this doesn't correct your problem, get back to us.

(Carburetor Adjustment - Single S/S Adjustable Needle Valve)
(J. Reeves)

Initial setting is: Slow speed = seat gently, then open 1-1/2 turns.

Start engine and set the rpms to where it just stays running. In segments of 1/8 turns, start to turn the S/S needle valve in. Wait a few seconds for the engine to respond. As you turn the valve in, the rpms will increase. Lower the rpms again to where the engine will just stay running.

Eventually you'll hit the point where the engine wants to die out or it will spit back (sounds like a mild backfire). At that point, back out the valve 1/4 turn. Within that 1/4 turn, you'll find the smoothest slow speed setting.

Note 1: As a final double check setting of the slow speed valve(s), if the engine has more than one carburetor, do not attempt to gradually adjust all of the valves/carburetors at the same time. Do one at a time until you hit the above response (die out or spit back), then go on to the next valve/carburetor. It may be necessary to back out "all" of the slow speed adjustable needle valves 1/8 turn before doing this final adjustment due to the fact that one of the valves might be initially set ever so slightly lean.

Note 2: If the engine should be a three (3) cylinder engine with three (3) carburetors, start the adjustment sequence with the center carburetor.

When you have finished the above adjustment, you will have no reason to move them again unless the carburetor fouls/gums up from sitting, in which case you would be required to remove, clean, and rebuild the carburetor anyway.
Thousands of parts in my remaining stock. Not able to list them all. Let me know what you need and I'll look it up for you. Visit my eBay auction at:

http://shop.ebay.com/Joe_OMC32/m.html?_dmd=1&_ipg=50&_sop=12&_rdc=1

[/QUOTE]
 
Ok. Now the carbis are clean. They were clean but had the corroded old red plugs (now black and in pieces) all through there. Also had some old thread tape in there too. Once I get the red plugs I will try your suggestions and report back. Is there anything I should be looking for or doing when putting the Carbis back on? Thanks
 
Make sure the float levels are proper............

(Carburetor Float Setting)
(J. Reeves)

With the carburetor body held upside down, the float being viewed from the side, adjust the float so that the free end of the float (the end opposite the hinge pin) is ever so slightly higher (just ever so slightly off level) than the other end. And when viewed from the end, make sure it is not cocked.
Thousands of parts in my remaining stock. Not able to list them all. Let me know what you need and I'll look it up for you. Visit my eBay auction at:

http://shop.ebay.com/Joe_OMC32/m.html?_dmd=1&_ipg=50&_sop=12&_rdc=1
 
Ok. So now have installed the red circle things and they are working ok. I have put the two brass screws back in and tried all the different settings as per above. It now is poring fuel out of both carbis! Not sure what is going on but fuel literally shoots out of the front of each carbi when starting the engine. Please help!
 
Also it's cranks and there is spark but just doesn't even want to kick over or cough. Any advice is greatly appreciated. Thanks
 
Fuel shooting out of the carburetors?

If fuel is shooting out of the carburetors when you pump the fuel primer bulb up hard, either the float needle valves are faulty and need replacing or/and the float level is not set properly.

Don't try all different needle valve settings..... set them exactly as I stated, THEN... when the engine is running, adjust them in the sequence I mentioned above.
 
Thanks heaps for your advice mate. I ended up getting another second hand carbi and have finally got it running. It runs well but now won't seem to idle properly. It seems to start of well and then after a 30 seconds starts to gradually increase in revs. Nothing seems to be moving etc and carbi sealed and set well so I don't know where else to look. Any advice appreciated. Thanks again so far.
 
Gradually increasing in rpm after running normally for 30 seconds indicates that the engine is starting to run lean on fuel, indicating a fuel/air leak at some point between the fuel pump and the fuel supply... OR... a failing fuel pump.

Try pumping the fuel primer bulb, acting as a manual fuel pump to see if that cures the condition.
 
Re: Evinrude 50hp 72 model won't start no spark

Thank you! It turned out to be a faulty fuel pump. Which has now been replaced and worked well. It ran for a short while no problems. Then next day went out to give it a start before taking it down to the water and it wouldn't start. Fuel is all good but now I have no spark? I have tested the trigger and it is producing power. I also have power going to the power pack from the trigger. I have replaced both coils with new ones. Same for the spark plugs. I have isolated the kill switch and still no go. I am lost at how to test the power pack ? Or if it may be the stator? (hope not). And how to test those? any advice is greatly appreciated. I am soo looking forward to getting this boat going sounded really nice when it was running a couple of days ago. Thanks again
 
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