Hello Gentlemens. Wondering if anyone has some experience changing the power pack on a 1996 Johnson 35 hp 3 cylinder. I bought this engine 4 years ago. The original engine was a tiller model that was converted to a remote by the previous owner. Engine worked fine until last year. It would misfire at high rpm and would misfire really badly when there was load at the back of my 15 ft aluminum boat or when the weather was warmer. The engine would also fail to start sometimes unless I get someone to lightly tap on the power pack while I turn the ignition key.
I ordered a new aftermarket pack from Ebay and installed it using the diagram from my Johnson manual.
The new power pack has 2 grounds while the original one only has one. Looks like the previous onwner/machanic taken out one of the grounds and modified the pack to have some kind of filament sticking out near the bottom on the pack. Any ideas that this is? Possibly the second ground? Not sure why the original power pack can run without having 2 grounds fixed to the block.
After installing the new pack, the engine fired right up every single time but sounded weak.
I used an inductive tach to check the rpm and got a reading of around 300 rpm (on a garden hose). The original power pack would turn the shaft about 1300 rpm on hose and 700 rpm when the boat is in the water.
I checked for spark on the new power pack. Cylinder 1 and 2 had no spark while cylinder 3 had spark. I pulled the plugs and noticed plugs 1 and 2 looked fouled while plug 3 looked alright. There is also some sludge leaving the exhaust. I suspect this was from the unburnt fuel/oil form cylinder 1 and 2 mixed with the exhaust fumes from cylinder 3. The original power pack had spark on all 3 cylinders and minimal residue coming out of prop exhaust.
I would think changing the power pack would be a simple swap. Not sure what I’m doing wrong. Any advice would be greatly appreciated.
I ordered a new aftermarket pack from Ebay and installed it using the diagram from my Johnson manual.
The new power pack has 2 grounds while the original one only has one. Looks like the previous onwner/machanic taken out one of the grounds and modified the pack to have some kind of filament sticking out near the bottom on the pack. Any ideas that this is? Possibly the second ground? Not sure why the original power pack can run without having 2 grounds fixed to the block.
After installing the new pack, the engine fired right up every single time but sounded weak.
I used an inductive tach to check the rpm and got a reading of around 300 rpm (on a garden hose). The original power pack would turn the shaft about 1300 rpm on hose and 700 rpm when the boat is in the water.
I checked for spark on the new power pack. Cylinder 1 and 2 had no spark while cylinder 3 had spark. I pulled the plugs and noticed plugs 1 and 2 looked fouled while plug 3 looked alright. There is also some sludge leaving the exhaust. I suspect this was from the unburnt fuel/oil form cylinder 1 and 2 mixed with the exhaust fumes from cylinder 3. The original power pack had spark on all 3 cylinders and minimal residue coming out of prop exhaust.
I would think changing the power pack would be a simple swap. Not sure what I’m doing wrong. Any advice would be greatly appreciated.