I have a 1976 17' Glasply runabout that I restored about 3 years ago. Originally it has a '92 Evinrude 70hp on it that after a bit of work ran perfectly. I'm a water skier though, and wanted more power, so I traded in the 70 on a 1993 140hp. This has proved to be a poor decision.
When the motor was first on the boat it seemed to run OK. Test run near the shop that I bought it from didn't show any problems.
Over the next month it started to show symptoms of running lean at idle. It would spit and sneeze and all of that. It didn't seem to be a fueling issue as the carbs were always full of fuel and squeezing the fuel bulb didn't do anything.
The first thing I did was rebuild all 4 carbs. This motor has the stupid plastic non-adjustable carbs which were a major pain to get to seal again, but I eventually got everything back on, with no change in performance.
Since then I've done plugs and plug wires, changed out all of the recirc fittings, put new throttle body gaskets on, and checked compression (145 in all cylinders)
The symptoms have done nothing but get worse, the motor now won't idle at all. It used to be it would spit and stutter for a while before it stalled, now it's almost immediate. If you rev it up, it runs perfectly, makes good power, no problems. Once you throttle back it starts to sneeze again, and quickly dies.
I'm really running out of things to check. I finally gave in and took it to a mechanic, I'm pretty new to outboards so I wanted to be sure I wasn't missing something simple. $500 later they told me they couldn't find anything wrong, and the next step they wanted to take was to pull the powerhead and check the lower crankshaft seal.
I'm now working on it again myself. I found that a different suffix of the 140 model came with a carburetor with an adjustable air bleed. I compared the part numbers for everything else around the upper carb body and found them the same, so I bought 4 of the upper bodies and put them on my existing lowers. This hasn't changed anything, adjusting the bleed screw doesn't make any difference. It's obvious that there is some sort of large air leak coming from somewhere else.
Just today I've started tearing apart the intake side of the motor again. My current plan is to replace all of the reed plates and all of the gaskets from the crankcase on out. The reed plates look just fine to me, no cracks or chunks missing, all of them seem to be sealing properly, but I'm so completely out of ideas that I don't know what else to try. There just aren't many other places for it to be leaking.
I have a really tough time believing what the shop told me about the lower crank seal. I asked another mechanic about that and he said that normally I would see evidence of rust in the lower cylinders if that seal was bad. Plus it just seems like a really strange part to fail so significantly. Should I actually pull the powerhead and replace this seal? What about the upper crankshaft seal? My Dad is starting to think I should just junk most of the motor and buy a reman'd short/long block. I'm having a hard time getting onboard with this as the current motor runs so well at speed.
If you made it this far, sorry for the long post. This boat was originally my grandfathers, and has a bit of nostalgia associated with it, I really really want to get it running again.
Does anyone else have any ideas of what I should look at?
When the motor was first on the boat it seemed to run OK. Test run near the shop that I bought it from didn't show any problems.
Over the next month it started to show symptoms of running lean at idle. It would spit and sneeze and all of that. It didn't seem to be a fueling issue as the carbs were always full of fuel and squeezing the fuel bulb didn't do anything.
The first thing I did was rebuild all 4 carbs. This motor has the stupid plastic non-adjustable carbs which were a major pain to get to seal again, but I eventually got everything back on, with no change in performance.
Since then I've done plugs and plug wires, changed out all of the recirc fittings, put new throttle body gaskets on, and checked compression (145 in all cylinders)
The symptoms have done nothing but get worse, the motor now won't idle at all. It used to be it would spit and stutter for a while before it stalled, now it's almost immediate. If you rev it up, it runs perfectly, makes good power, no problems. Once you throttle back it starts to sneeze again, and quickly dies.
I'm really running out of things to check. I finally gave in and took it to a mechanic, I'm pretty new to outboards so I wanted to be sure I wasn't missing something simple. $500 later they told me they couldn't find anything wrong, and the next step they wanted to take was to pull the powerhead and check the lower crankshaft seal.
I'm now working on it again myself. I found that a different suffix of the 140 model came with a carburetor with an adjustable air bleed. I compared the part numbers for everything else around the upper carb body and found them the same, so I bought 4 of the upper bodies and put them on my existing lowers. This hasn't changed anything, adjusting the bleed screw doesn't make any difference. It's obvious that there is some sort of large air leak coming from somewhere else.
Just today I've started tearing apart the intake side of the motor again. My current plan is to replace all of the reed plates and all of the gaskets from the crankcase on out. The reed plates look just fine to me, no cracks or chunks missing, all of them seem to be sealing properly, but I'm so completely out of ideas that I don't know what else to try. There just aren't many other places for it to be leaking.
I have a really tough time believing what the shop told me about the lower crank seal. I asked another mechanic about that and he said that normally I would see evidence of rust in the lower cylinders if that seal was bad. Plus it just seems like a really strange part to fail so significantly. Should I actually pull the powerhead and replace this seal? What about the upper crankshaft seal? My Dad is starting to think I should just junk most of the motor and buy a reman'd short/long block. I'm having a hard time getting onboard with this as the current motor runs so well at speed.
If you made it this far, sorry for the long post. This boat was originally my grandfathers, and has a bit of nostalgia associated with it, I really really want to get it running again.
Does anyone else have any ideas of what I should look at?
and low and behold...... he has posted. You have the best involved.