3.5 Hp Tecumseh Engine Manual
We picked up a 12' boat the other day with a supposedly 1972 sears 3.5hp outboard. The previous owner said the engine started great and we didn't have a trash can to dunk it in so we took their word for it. I got home dunked the lower unit in water and started it up.
It starts and idles but misfires and will not rev up at all.I cleaned some rust out of the carb and added an inline fuel filter between the tank and carb. After cleaning the carb it barely ran any better. Randomly, after running it several times it took off and revved up running very smooth, then stalled and the next time I tryed starting it the misfires and bogging was back.I've looked at what I think is everything with the fuel system to no avail. I installed a new spark plug although with the plug out lying against the engine the spark looks a little on the yellow side. Could this be a bad condenser?
With my cheapo digital multimeter on the 2000 k ohms setting black lead on condenser body red lead on condenser wire the ohms jump rapidly up to infinite reading on my meter.The points look OK from what I know not pitted or burnt up although possibly a little dirty? I don't know much about points ignition systems.I'd really like to fully understand and run this old gal rather than pay through the nose for a newer engine. Looking for advice.thanks in advance. The trick in regards to cleaning points with file or emery paper is to run a sheet of paper thru the points a couple times to remove all the loose crap that the sandpaper left behind.The grit on sandpaper can be conductive and not let the points work as well or will let them burn quicker.I had this same exact problem with a HH60. To get it running as good as I did, I found a ignition wire crimped behind the coil and I repaired that.If the wire is crimped or whatever and the gap is shorter than the plug, the fire will jump when the engine is reved up as it is more voltage.BTW, I had put a new carb on the engine from ebay and it didnt change the problems when I was working on the engine, so I had no real choice but go towards the ignition.IF you need a carb, get the tecumseh part number and paste it in the ebay search engine. ALOT of the carbs for tecumseh engines are on ebay for around 25 to 35 dollars.
Well, at this point (no pun intended) it only sparks when it feels like it and only for a few revolutions and then stops. The engine will sometimes fire for a second and then die.
I'm about stumped the magnets seem OK they draw a screwdriver in from 3/4' away. The coil, ignition wire, plug, condenser and points are all new.
3.5 Hp Tecumseh Engine Manual Download
Point gap set at.020' plug gap set at.030' New plug.9k ohms resistance from the end of the plug wire to ground.8 ohms resistance on the coil primary windingThe flywheel key is there and intact. The gap between the laminations and the flywheel magnets looks OK its very tight but not touching and the laminations are riveted on anyhow.If someone can figure this out you would truly be my hero lol. Update: holy hell I got the damn thing to run half decent. I gapped the points a little tighter.019' and really pushed them against the feeler gauge. It has been starting now and running half decent. It will rev up but sometimes sputter or hesitate on acceleration or decelleration.
Just cutting out some. Dosn't like to idle all that well either.
Screwed around with the carb adjustments a lot too. It dosn't even seem to want to start without the idle screw being about 2.5 turns out. The Main screw needed turned in to get it to rev clean.
3.5 Hp Tecumseh Engine Manual Transmission
Gosh this thing is finicky. I'll take any pointers on how to fine tune this thing.- Post added at 05:44 PM - Previous post was at 05:42 PM -John I just saw your post. Little big city 3. I'll try closing them up a little more.