Alan Serven
Cadet
- Joined
- Jul 4, 2006
- Messages
- 10
I apologize for the length of this at the outset, but sometimes the details can hold clues...
After some routine maintanence work earlier this year (mainly replacing the plugs), I tried to start my 94 175 HP Johnson. Finding the battery had not held the charge I put in it, I tried jumping it from my car. Many tries, and while it cranked convincingly, I had little success in actually getting it to start. Even when it did start (rarely), it wouldn't run for more than 30 or 45 seconds before stalling and was very hard to restart.
A couple of weeks later I replaced the battery and the engine started (about the second or third key turn) and run for at least 10 minutes before I shut it off. Odd, I thought. Tried it again a week later with essentially the same results.
Heartened by the trials in the driveway, I went to the lake Saturday. Started at the ramp (second or third key turn, again), idled out through the no-wake, opened it up and made about 1/2 mile at WOT before I stopped (put it in neutral) to double-check water flow from the water pump. When I put it back in gear, it stalled. For a while it would start by advancing the throttle and would run at 1500 RPM or so, but as soon as I took it back to idle and tried to put it in gear, it would stall out. As time progressed, it would die as soon as I put it in neutral. Once I reached that point, nothing I tried would get it to start at all. For the first time in my boating life, I had to be towed back to the ramp.
Some digging through my shop manual revealed a note that the wrong spark plugs would cause all kinds of evils. Checking, I found that I had been sold the wrong spark plugs (J4C's). Encouraged that I had uncovered the root of my problems, I bought new QL78YC's on the way home tonight and installed them. The engine started on the first turn of the key!!! YIPPEE. Fooling around a little, I ran the throttle up and down (never past 1,500 RPM with the garden hose for cooling). After it had warmed up, again it would idle for 15 to 30 seconds at about 600 RPM, then die. It always restarted, ran at 1,000 RPM for a few moments, then dropped to 600 and died.
Advancing the throttle to kick it to 1,500 RPM always gave nice, smooth performance.
I tried treating it with OMC Engine Tuner - No change.
P.S. - I was running with the oil level sender disconnected. The the replacement got here yesterday and solved a prior issue with a continuous warning horn when I turned the key to "run". Also, I replaced the fuel pump a year or two ago. Other than that, there has been NO repair work on the engine, nor has it ever been tuned - it has always run great. Well, almost always. I did notice last year it was a bit hard to start when warmed up after we had sit for an hour or two and didn't like to putt along at idle, which is why I replaced the plugs.
Any ideas?
After some routine maintanence work earlier this year (mainly replacing the plugs), I tried to start my 94 175 HP Johnson. Finding the battery had not held the charge I put in it, I tried jumping it from my car. Many tries, and while it cranked convincingly, I had little success in actually getting it to start. Even when it did start (rarely), it wouldn't run for more than 30 or 45 seconds before stalling and was very hard to restart.
A couple of weeks later I replaced the battery and the engine started (about the second or third key turn) and run for at least 10 minutes before I shut it off. Odd, I thought. Tried it again a week later with essentially the same results.
Heartened by the trials in the driveway, I went to the lake Saturday. Started at the ramp (second or third key turn, again), idled out through the no-wake, opened it up and made about 1/2 mile at WOT before I stopped (put it in neutral) to double-check water flow from the water pump. When I put it back in gear, it stalled. For a while it would start by advancing the throttle and would run at 1500 RPM or so, but as soon as I took it back to idle and tried to put it in gear, it would stall out. As time progressed, it would die as soon as I put it in neutral. Once I reached that point, nothing I tried would get it to start at all. For the first time in my boating life, I had to be towed back to the ramp.
Some digging through my shop manual revealed a note that the wrong spark plugs would cause all kinds of evils. Checking, I found that I had been sold the wrong spark plugs (J4C's). Encouraged that I had uncovered the root of my problems, I bought new QL78YC's on the way home tonight and installed them. The engine started on the first turn of the key!!! YIPPEE. Fooling around a little, I ran the throttle up and down (never past 1,500 RPM with the garden hose for cooling). After it had warmed up, again it would idle for 15 to 30 seconds at about 600 RPM, then die. It always restarted, ran at 1,000 RPM for a few moments, then dropped to 600 and died.
Advancing the throttle to kick it to 1,500 RPM always gave nice, smooth performance.
I tried treating it with OMC Engine Tuner - No change.
P.S. - I was running with the oil level sender disconnected. The the replacement got here yesterday and solved a prior issue with a continuous warning horn when I turned the key to "run". Also, I replaced the fuel pump a year or two ago. Other than that, there has been NO repair work on the engine, nor has it ever been tuned - it has always run great. Well, almost always. I did notice last year it was a bit hard to start when warmed up after we had sit for an hour or two and didn't like to putt along at idle, which is why I replaced the plugs.
Any ideas?
