eavega
Lieutenant
- Joined
- Apr 29, 2008
- Messages
- 1,377
Hey guys. Sorry in advance for the long post. I just have just included a lot of information trying to anticipate different troubleshooting scenarios.
I have a 1976 70 HP Johnson outboard on my 15' tri-hull. Went out fishing on Saturday and have had the worst kind of problem; the kind that comes and goes with no rhyme or reason. Just for the record, within the last two months I have de-carbed the motor, replaced the impeller, new plugs, fresh fuel, changed the gearcase oil. Carbs were professionally re-built last year in September. I've only run stabilized 50:1 premix fuel (with the exception of the sea-foam decarb mix). Motor was idle from November until first week of March, but has been out on the water 3 or 4 times since then. First time with the new plugs, though. Motor is not overheating. I have honestly not tested compression after the de-carb but before the decarb I had 110 evenly across all three cylinders.
1. Started the motor in the driveway on muffs. Motor starts right up.
2. We get to the ramp, and my fishing buddy says he will get on the boat to get it started and I can back it down the ramp. Boat in the water, but I see my buddy is having problems getting it going. Cranking just fine, but motor is not catching. forgot to tell him that I have installed an overboard safety switch on the ignition. Pop the killswitch in. Motor still won't start. I take a look, and see my buddy has put the fuel line connector on backwards at the tank so there was no fuel going to the motor. Once we get the fuel line properly connected and primed the carbs (lesson learned, don't rely on anyone to go through your startup procedure), motor fires right off and we are on our way.
3. First fishing spot reached in about 5 min at WOT. Kill the motor. Fish for about 30 min. Nothing biting, lets move on. Crank the motor, starts on the second bump of the key. after about a minute at WOT I start getting a hesitation, and motor dies. Primer bulb is gone soft. I squeeze the bulb a couple of times, start it up again, starts on the first bump, throttle up, goes a couple of seconds and dies. Same procedure again, this time I take the cover off the motor so I can see if something has gone wrong, start it up and no hesitation, throttle up and no problems, get to our next fishing spot. I didn't spot any leaking exhaust to make me think the motor was suffocating itself, so I put the cover back on. Fish are biting here so we are on the spot for about an hour and half or so.
4. Time to wrap it up and go home. try to start the motor, and its not starting. Crank, crank, crank. Rest. Check the bulb, its soft and full of air, so I prime and try to start again. Nothing. Squeeze bulb until it gets hard again, push in the choke, crank crank crank. Nothing. Pull the cover, pull the top plug to see if that can tell me something. Plug is not unusually wet as I would expect it to be if I was cranking but was not discolored in any unexpected way. I attached a spark tester to the lead, but don't pull the other two plugs In fact I had also replaced the top plug (didn't want to drop it in the water or something like that). Tell my buddy to crank it, and this time the motor catches and is running on two cylinders (since the top plug does not have the lead attached). Tell my buddy to kill the motor, reattach the top lead to the plug, crank it, starts right up.
5. WOT run for about 10 min to get back to the dock. Drop off my buddy to go get the trailer, meanwhile I am idling just off the ramp waiting our turn. Motor behaves perfectly. We get the boat back on the trailer, a bit of idle speed maneuvering in forward and reverse (missed the trailer once and had to try again). No more misses, hesitations, random loss of power, etc.
So I can't nail it down to "motor warmed up and something shorted", "Only happens at WOT", "Only happens at idle", "Hard to start", because I had problems at any one of those points, but not all the time. Here is my speculation, but I am looking for suggestions to try to narrow the scope of my troubleshooting.
The problem starting at the ramp was purely the fuel line not being connected. What I am speculating is that when my buddy popped the line in backwards (i.e. the ball valve end on the pointy prong that locks the connector in place) he somehow damaged the fuel line to the point that its now leaking air into the fuel system and/or causing the line to lose prime. This would explain the sudden loss of power at WOT on our second long run, but I can't see how that would cause the difficult start on our last run unless by priming and choking the motor I flooded it and that resolved itself in the time it took me to troubleshoot the ignition system.
Can anyone offer any alternate explanation or possible troubleshooting that I should do before heading back out? I'm replacing the fuel line with a brand-new one that already has all the proper connectors attached with the metal clamps (until now I have been using zip ties on the fittings, and I think that is a no-no). My limited experience tells me that this is a fuel problem and not an ignition problem, mostly because once its running, it runs well. Any advice would be greatly appreciated.
Rgds
I have a 1976 70 HP Johnson outboard on my 15' tri-hull. Went out fishing on Saturday and have had the worst kind of problem; the kind that comes and goes with no rhyme or reason. Just for the record, within the last two months I have de-carbed the motor, replaced the impeller, new plugs, fresh fuel, changed the gearcase oil. Carbs were professionally re-built last year in September. I've only run stabilized 50:1 premix fuel (with the exception of the sea-foam decarb mix). Motor was idle from November until first week of March, but has been out on the water 3 or 4 times since then. First time with the new plugs, though. Motor is not overheating. I have honestly not tested compression after the de-carb but before the decarb I had 110 evenly across all three cylinders.
1. Started the motor in the driveway on muffs. Motor starts right up.
2. We get to the ramp, and my fishing buddy says he will get on the boat to get it started and I can back it down the ramp. Boat in the water, but I see my buddy is having problems getting it going. Cranking just fine, but motor is not catching. forgot to tell him that I have installed an overboard safety switch on the ignition. Pop the killswitch in. Motor still won't start. I take a look, and see my buddy has put the fuel line connector on backwards at the tank so there was no fuel going to the motor. Once we get the fuel line properly connected and primed the carbs (lesson learned, don't rely on anyone to go through your startup procedure), motor fires right off and we are on our way.
3. First fishing spot reached in about 5 min at WOT. Kill the motor. Fish for about 30 min. Nothing biting, lets move on. Crank the motor, starts on the second bump of the key. after about a minute at WOT I start getting a hesitation, and motor dies. Primer bulb is gone soft. I squeeze the bulb a couple of times, start it up again, starts on the first bump, throttle up, goes a couple of seconds and dies. Same procedure again, this time I take the cover off the motor so I can see if something has gone wrong, start it up and no hesitation, throttle up and no problems, get to our next fishing spot. I didn't spot any leaking exhaust to make me think the motor was suffocating itself, so I put the cover back on. Fish are biting here so we are on the spot for about an hour and half or so.
4. Time to wrap it up and go home. try to start the motor, and its not starting. Crank, crank, crank. Rest. Check the bulb, its soft and full of air, so I prime and try to start again. Nothing. Squeeze bulb until it gets hard again, push in the choke, crank crank crank. Nothing. Pull the cover, pull the top plug to see if that can tell me something. Plug is not unusually wet as I would expect it to be if I was cranking but was not discolored in any unexpected way. I attached a spark tester to the lead, but don't pull the other two plugs In fact I had also replaced the top plug (didn't want to drop it in the water or something like that). Tell my buddy to crank it, and this time the motor catches and is running on two cylinders (since the top plug does not have the lead attached). Tell my buddy to kill the motor, reattach the top lead to the plug, crank it, starts right up.
5. WOT run for about 10 min to get back to the dock. Drop off my buddy to go get the trailer, meanwhile I am idling just off the ramp waiting our turn. Motor behaves perfectly. We get the boat back on the trailer, a bit of idle speed maneuvering in forward and reverse (missed the trailer once and had to try again). No more misses, hesitations, random loss of power, etc.
So I can't nail it down to "motor warmed up and something shorted", "Only happens at WOT", "Only happens at idle", "Hard to start", because I had problems at any one of those points, but not all the time. Here is my speculation, but I am looking for suggestions to try to narrow the scope of my troubleshooting.
The problem starting at the ramp was purely the fuel line not being connected. What I am speculating is that when my buddy popped the line in backwards (i.e. the ball valve end on the pointy prong that locks the connector in place) he somehow damaged the fuel line to the point that its now leaking air into the fuel system and/or causing the line to lose prime. This would explain the sudden loss of power at WOT on our second long run, but I can't see how that would cause the difficult start on our last run unless by priming and choking the motor I flooded it and that resolved itself in the time it took me to troubleshoot the ignition system.
Can anyone offer any alternate explanation or possible troubleshooting that I should do before heading back out? I'm replacing the fuel line with a brand-new one that already has all the proper connectors attached with the metal clamps (until now I have been using zip ties on the fittings, and I think that is a no-no). My limited experience tells me that this is a fuel problem and not an ignition problem, mostly because once its running, it runs well. Any advice would be greatly appreciated.
Rgds
