weak spark & sniffle ? 1989 Johnson gt150

[kknopp01]

weak spark & sniffle ? 1989 Johnson gt150

Hey all,
Have a 1989 johnson gt150 i have been restoring. Finally got time to put it in the water today but the motor struggles to stay idling and intermittently will sniffle/sneaze. Tho its starts easily and can keep it on by bumping the throttle to 1200ish, the motor wont idle down and stay running for more than 30 seconds.

I got home, pulled and cleaned the spark plugs and found each cylinder has spark. touched each to the block while having others grounded and water running via muffs.

Are these the same issue(weak spark and sniffling/not wanting to idle) ? and where should i start looking ?

Thanks!

have new gas (50:1), new filter, fuel pumps, and a carb rebuild all less than 3 weeks ago, but this is the second time gas has been pushed through the motor since last sunday.

[Joe Reeves]

weak spark & sniffle? 1989 Johnson gt150. The motor struggles to stay idling and intermittently will sniffle/sneaze. it starts easily and can keep it on by bumping the throttle to 1200ish, the motor wont idle down and stay running for more than 30 seconds.

I cleaned the spark plugs and found each cylinder has spark. touched each to the block while having others grounded.

Carb rebuild all less than 3 weeks ago, but this is the second time gas has been pushed through the motor since last Sunday.

A sneeze... what sounds like a mild backfire, is caused by a lean condition of one or more carburetors. A wrong idle air bleed installed, a leaking carburetor to intake manifold gasket leaking, a clogged fuel passageway, something on that order.

With the engine running and sneezing, stick two fingers into the carburetor throats. When the engine smooths out, you have found the offending carburetor.

On a flushette, the neutral idle should be, depending on the shaft length:

20" shaft = 1000 rpm

25" shaft = 1200 rpm

NOTE: Checking spark via using the spark plugs is a waste of time! The spark, with all plugs removed should jump a 7'16" gap with a strong blue lightning like flame... a real SNAP! Does it?

What is the actual compression psi of all the individual cylinders?

Please do not reply saying the spark is great and the compression is good or some such thing as this means nothing to us.

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(Spark Tester - Home Made)
(J. Reeves)

You can use a medium size philips screwdriver (#2 I believe) inserted into the spark plug boot spring connector, then hold the screwdriver shank approximately 7/16" away from the block to check the spark or build the following:

A spark tester can be made with a piece of 1x4 or 1x6, drive a few finishing nails through it, then bend the pointed ends at a right angle. You can then adjust the gap by simply twisting the nail(s). Solder a spark plug wire to one which you can connect to the spark plug boots, and a ground wire of some kind to the other to connect to the powerhead somewhere. Use small alligator clips on the other end of the wires to connect to ground and to the spark plug connector that exists inside of the rubber plug boot.

Using the above, one could easily build a spark tester whereas they could connect 2, 4, 6, or 8 cylinders all at one time. The ground nail being straight up, the others being bent, aimed at the ground nail. A typical 4 cylinder tester follows:

..........X1..........X2

.................X..(grd)

..........X3..........X4

Thousands of parts in my remaining stock. Not able to list them all. Let me know what you need and I'll look it up for you. Visit my eBay auction at:

http://shop.ebay.com/Joe_OMC32/m.htm..._sop=12&_rdc=1
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[kknopp01]

Awesome! will hunt down the carbs, had planned to take the apart and soak them due to the "sniffle"

I will recheck the compression, at one point, when i started....they all were between 88 and 96 i believe

i bought carb kits for this motor, could the wrong air bleed still be a possibility?

by sticking fingers into the carbs, am i pushing them at all or just placing them?

Thanks again!