AntiqueTbird
Cadet
- Joined
- Jul 1, 2012
- Messages
- 29
picked up the 18' Thunderbird Formula With a Johnson 140 on it for a song. only 216 hours on the motor for real.
original owner for 35 years. garage kept for 30 years last used 7 years ago. Serviced religiously and the last service record is from 7 years ago. the guy moved had financial problems and hadn't run it at all in the last 5 years. it also sat in the florida sun for those 5 years.
1. Service record said 130# on all four cylinders and that was accurate.
2. So I hooked up a battery and cranked it looking for spark etc.. great strong spark on it.
then I did the responsible thing and cleaned the fuel tank, replaced all fuel line related components. pulled the carbs and cleaned them although they were truely very clean.
new impeller and impeller body. new l.u. oil.
prop was in nearly perfect condition.
so I was even more responsible and got some muffs, mixed some fuel, and cranked her up.
warm up lever to 3/4 a little electric choke and she was running well.
got her water and it turns out the prop hub is spun. my weekend is over as work follows the next day.
new weekend new prop and she's running. wot and she's sluggish. planes but with only me aboard. idle is smooth but no performance. having spent many florida keys based vacations in a '77 23' seacraft with a pair of these very 140's on it I know she should scream. but she doesn't.
I read re-read and read again. I could only come to the conclusion that I needed to replace the plugs and rebuild the carbs completely with new rebuild kits.
that was done. and now she is barely running at 2000r's revs right up to 5500 in neutral on the water but in gear she'll die at anything less than half throttle which tachs at about 2500. Try and open her up in gear and she spits sputters and sounds to be missfiring.
so took her home. hooked up the muffs and did several different things. using all good snapon tools for diagnostics.
1. check compression. all 130psi.
2. check spark. consistent 7/16 jump with same color.
3. hooked up inductive timing gun and timing on cylinder1 at full open was 24? ( assume adjusted 4? from 28? because of new knowledge)
4. pulled fuel filter and drained it. clean.
5. pulled carbs checked them all out again. floats are adjusted perfectly float needles are still brand new looking bowls are perfectly clean. idle orifices are clean and freely flowing.
6. looked at the reeds through the intake throats and they look good.
put it all back together and still not idling at all. below 2000 r's she spits sputters and dies.
have not checked spark voltage with a dva. just don't have one of them. need to get one and check that I guess.
beyond these things I am stumped.
I'll add that at that high idle 2000r's if I swing the timing further advanced the sputtering stops but the revs go to 3700. but if I manually advance the timing and lower the warmup lever to where warm idle is (like 0 throttle.) she either doesn't. start or starts, revs high, and dies.
hooking up the battery charger and packing it in until Wednesday.
let me know if there are some dumb gotchas that I missed.
have the seloc manual and at this point I am stuck.
original owner for 35 years. garage kept for 30 years last used 7 years ago. Serviced religiously and the last service record is from 7 years ago. the guy moved had financial problems and hadn't run it at all in the last 5 years. it also sat in the florida sun for those 5 years.
1. Service record said 130# on all four cylinders and that was accurate.
2. So I hooked up a battery and cranked it looking for spark etc.. great strong spark on it.
then I did the responsible thing and cleaned the fuel tank, replaced all fuel line related components. pulled the carbs and cleaned them although they were truely very clean.
new impeller and impeller body. new l.u. oil.
prop was in nearly perfect condition.
so I was even more responsible and got some muffs, mixed some fuel, and cranked her up.
warm up lever to 3/4 a little electric choke and she was running well.
got her water and it turns out the prop hub is spun. my weekend is over as work follows the next day.
new weekend new prop and she's running. wot and she's sluggish. planes but with only me aboard. idle is smooth but no performance. having spent many florida keys based vacations in a '77 23' seacraft with a pair of these very 140's on it I know she should scream. but she doesn't.
I read re-read and read again. I could only come to the conclusion that I needed to replace the plugs and rebuild the carbs completely with new rebuild kits.
that was done. and now she is barely running at 2000r's revs right up to 5500 in neutral on the water but in gear she'll die at anything less than half throttle which tachs at about 2500. Try and open her up in gear and she spits sputters and sounds to be missfiring.
so took her home. hooked up the muffs and did several different things. using all good snapon tools for diagnostics.
1. check compression. all 130psi.
2. check spark. consistent 7/16 jump with same color.
3. hooked up inductive timing gun and timing on cylinder1 at full open was 24? ( assume adjusted 4? from 28? because of new knowledge)
4. pulled fuel filter and drained it. clean.
5. pulled carbs checked them all out again. floats are adjusted perfectly float needles are still brand new looking bowls are perfectly clean. idle orifices are clean and freely flowing.
6. looked at the reeds through the intake throats and they look good.
put it all back together and still not idling at all. below 2000 r's she spits sputters and dies.
have not checked spark voltage with a dva. just don't have one of them. need to get one and check that I guess.
beyond these things I am stumped.
I'll add that at that high idle 2000r's if I swing the timing further advanced the sputtering stops but the revs go to 3700. but if I manually advance the timing and lower the warmup lever to where warm idle is (like 0 throttle.) she either doesn't. start or starts, revs high, and dies.
hooking up the battery charger and packing it in until Wednesday.
let me know if there are some dumb gotchas that I missed.
have the seloc manual and at this point I am stuck.