1969 6r69m 6hp Starts, idles, revs real high, then dies

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texas_salt

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- sprayed, soaked overnight, and rebuilt the carb
- replaced all fuel lines
- replaced entire ignition system. Coils. Condensers. Cleaned points. Gapped at .020. New spark plugs and wires.
- flywheel torqued at 40
- both cylinders have spark
- replaced thermostat/thermostat gasket

Current issue:

1. Sometimes it'll start, and idle for about 10 seconds, then die.
2. Other times it'll start, idle, rev up REALLY high, then die.

I'm thinking fuel related?

Observations:
The bulb was NOT stiff after it died one time. But sometimes it is.
On my millionth attempt, I manually pumped the bulb. It ran for a little longer than before, revved up REALLY high, then died.
I'm going to check the compression tomorrow.

This is starting to drive me nuts.
 
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texas_salt

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P.S. the motor also came with a 3 gallon portable tank. There is no manual vent, its in the cap. I cant help but wonder if that could be a culprit.
 

Michawilden

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Starting of with the basics, Does the motor have high enough compression on both cylinders? Low compression can induce hard starting and poor idle. What is the history of the engine? Assuming the compression and bearings are good:
Reving up high before it dies indicates a starvation of fuel. Might be caused by an old fuel pump but that does not initiate hard starting. Are you sure you assembled the carb in the correct order with the proper floater height? How does the motor react to throttle if it starts up? Does it die or does it rev up?
If you suspect the fuel tank, just leave the cap off.
 

texas_salt

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Apparently this isnt totally a bad thing on older motors. Also looks to be running on one cylinder. About to dive in and find out whats wrong
 

oldboat1

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indicated earlier both cylinders have spark. Need to test spark with an adjustable tester. Don't overlook clips in the boots (need solid contact with plug wire inner core -- solid core wire).

If you first resolve ignition issues: Running out of fuel (lean) will give you high rpms before quitting. Can't rule out a fuel pump issue if unable to keep it running, and runs out of fuel. As you started with the carb, probably should see that through -- complete disassembly before cleaning? How complete? Routine is to physically clean out all passages after soaking. Set the low speed needle 1 1/2 out initially -- if adjusting makes no difference, the idle passages aren't clear.

Your compression should be good enough. Make sure it's pumping water out of the leg, even with brief running.
 

texas_salt

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indicated earlier both cylinders have spark. Need to test spark with an adjustable tester. Don't overlook clips in the boots (need solid contact with plug wire inner core -- solid core wire).

If you first resolve ignition issues: Running out of fuel (lean) will give you high rpms before quitting. Can't rule out a fuel pump issue if unable to keep it running, and runs out of fuel. As you started with the carb, probably should see that through -- complete disassembly before cleaning? How complete? Routine is to physically clean out all passages after soaking. Set the low speed needle 1 1/2 out initially -- if adjusting makes no difference, the idle passages aren't clear.

Your compression should be good enough. Make sure it's pumping water out of the leg, even with brief running.

Flywheel back off. (Top cylinder not firing). The point gap was x2 as big. Fixed back and adjusted to .20. Still no spark. The multimeter has continuity from the coil ground to the clip in the boot (if this helps). Brand new wires, boots, etc.

The ignition cable is 7mm stranded core. I have reseated (repunctured) the metal boot connector multiple times into the wire. No luck. I even tested with the boot off and just the connector (to make sure there was contact. Point was cleaned last night. Just cleaned again

Im using an inline spark plug tester. Plugs are grounded. Bottom cylinder repeatedly shows spark (inline tester lights up). Will not start up with top cylinder. Only bottom. Def a spark issue.

Im wondering if the condensor/coil is bad. Off to check proper testing on these (again)
 
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texas_salt

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Tested everything. Only logical answer left was the wire wasnt well on the coil. So i cut it, reseated it, and now I have spark on both.

Alas, back to the original issue.

It runs better. But its still all over the place when it runs. 5-6 pulls to start. Sometimes with choke on. Sometimes with off. (I seem to have better luck with choke off)

It idles REALLY high.

And everytime the engine dies, the bulb is soft. Is this an indication of anything?

Also, should the portable tank be level with the motor or should the fuel pump have no issue?.
 
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oldboat1

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assume you are testing in a barrel with plenty of water. Can't do much on muffs. Try setting the tank up higher and see if that makes a difference -- sounds to me like a fuel pump issue, but guessing (and assuming no continued issues with the carb). LeeRoy's Ramblings has some good info on rebuilding, with a breakdown showing assembly.
 

ondarvr

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The bulb won't be hard after the motor starts, but it shouldn't collapse. If squeezing the bulb helps, then it's either a bad fuel pump or an air leak, but squeezing the bulb should keep it running until a minute or so after you stop.

Dying in ten seconds wouldn't indicate a fuel pump, but is still most likely from a fuel restriction if it revs up first.
 

texas_salt

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Leeroys ramblings is an awesome source. I pumped with the bulb, no leaking coming from the back of the fuel pump. Can check that issue off.

I then did the pump the bulb while running test. At no point did it die while I was pumping. It dies a little after, which I assume is just from the full bowl delay.

A real selling point is that as it was dying, I pumped the bulb and it seemed to get going again.

Leaning towards the fuel pump now. No signs of leaks anywhere.
 

oldboat1

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Additionally, are you pretty good at setting the air/fuel mix (idle or slow speed needle)? The standard method is to lean it out, with a corresponding increase in rpms. Throttle it down, and go back to setting the mix -- repeat the process. Looking for the leanest setting with smooth running, no lean sneeze, shifts in and out of gear without stumbling or stalling. If stalling, likely need to tweak the setting a little richer (counterclockwise).

With the high idle rpms you describe, could also be your throttle setting (i.e., slow/idle throttle speed setting). Not sure what idle stop you have on the '69 (might still be the plastic screw) -- throttle stop may be set too high, not throttling down. Put another way, you may get an rpm increase based on air/fuel adjustment, but unable to throttle down because of idle stop setting.

If your carb is clean and fuel supply OK, maybe you just haven't gotten it dialed it in yet after carb work.

(and 50:1 mix, btw, and might not hurt to unscrew the tank cap a little just for grins.)
 

oldboat1

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Leeroys ramblings is an awesome source. I pumped with the bulb, no leaking coming from the back of the fuel pump. Can check that issue off.

I then did the pump the bulb while running test. At no point did it die while I was pumping. It dies a little after, which I assume is just from the full bowl delay.

A real selling point is that as it was dying, I pumped the bulb and it seemed to get going again.

Leaning towards the fuel pump now. No signs of leaks anywhere.

oops. typing while you were posting.

agree -- sounds like a failing fuel pump.

[edit. btw, fuel pump info, in case you hadn't drilled down to that yet -- http://www.leeroysramblings.com/Rebuilding_fuelpump.htm ]
 
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texas_salt

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Additionally, are you pretty good at setting the air/fuel mix (idle or slow speed needle)? The standard method is to lean it out, with a corresponding increase in rpms. Throttle it down, and go back to setting the mix -- repeat the process. Looking for the leanest setting with smooth running, no lean sneeze, shifts in and out of gear without stumbling or stalling. If stalling, likely need to tweak the setting a little richer (counterclockwise).

With the high idle rpms you describe, could also be your throttle setting (i.e., slow/idle throttle speed setting). Not sure what idle stop you have on the '69 (might still be the plastic screw) -- throttle stop may be set too high, not throttling down. Put another way, you may get an rpm increase based on air/fuel adjustment, but unable to throttle down because of idle stop setting.

If your carb is clean and fuel supply OK, maybe you just haven't gotten it dialed it in yet after carb work.

(and 50:1 mix, btw, and might not hurt to unscrew the tank cap a little just for grins.)


http://forums.iboats.com/forum/engi...dle-mixture-intial-setting-johnson-6-hp-6r69m

Yeah there doesnt seem to be an idle screw on this model. The low speed needle at the top of the car is the idle adjustment. Even at the suggested needle settings its at high (and loud) RPM. After I start it, I have to immediately drop the throttle to "slow". This is all in neutral ofcourse.

I have to say, the throttle "start" position on the carb is very close to full wide-open-throttle.
 

racerone

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Check the sector gear and pinion on the end of the throttle shaft.-Check the gears where the handle folds.---Something is wrong if " start " gets you full throttle.
 

texas_salt

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Life is much easier now with that top cylinder now firing. Real glad I bought an inline spark tester. So much easier.

Anyway, im going to look into the high rpm issue. I wonder if the teeth are not aligned right after the shifter arm.

There is maybe an inch from full throttle and "start" on the "blade" that turns the butterfly. Even shift seems like high rpm.
 

texas_salt

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Start position

mbk37a.jpg
 

ondarvr

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The shift and start marks on the handle are rarely in the correct place after a few years, most people never look them. If it idles and the throttle plate in the carb opens completely then it's working correctly, if it doesn't open completely it needs to be adjusted so it does.
 
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