1960 18HP ... Moving good parts from overheated Engine over to a new Engine

[wadeatl]

Several months back I changed my impeller on our 1960 18HP and we took it out without insuring the pump was working (yes I know .. not good). In the end the lower rubber grommet was bent over on the copper tube. The motor overheated and we lost compression. Fast forward .. we were able to find another 1960 18HP locally with good compression 95psi in both cylinders. My thought process all along was to move over the carb that recently had a carb kit and a new fuel pump to the new engine. I thought for sure it would fire right up .. but no. Next it was time to test the spark. So tested the spark and both pulled great spark at 1/4". Next step was to check the points and timing. While adjusting the upper cylinder points I noticed the hold down screw was stripped and there was no way to hold the points in place. So I pulled the entire ignition system off the old 18HP and put on the new (to us) motor. Again .. I thought for sure it would power right up ... but no.

When I go to start her .. she act like she is going to start on the first pull. After that nothing .. after 4-5 pulls I start to see gas dripping out of the exhaust port onto the ground. I have tried multiple times with choke .. no choke .. the throttle in different positions and in the end no go.

So two thoughts .. one is that I kept the top side of the carb from from the new (to us) motor. I pulled the low speed needle .. sprayed carb cleaner in the low speed jet hole .. added a new cork gasket .. screwed it in to lightly closed and out 1.5 turns. I also made sure the float was level when swapping parts. So thats one thought .. could there be something else in the top side of the carb that I should have cleaned or modified? Second thought is the new (to us) engine has a different shut-off button/switch .. could the switch be bad? My thought is if the switch was bad I would not get spark?

I appreciate any help or guidance!

 

[RCO]

Did you make sure that the main nozzle gasket was there when you put the carb back together (1/4" round gasket)? Compression numbers? Coils not cracked, and front coil going to top cylinder? I have seen a couple with mouse nests packed into the exhaust to the point that they will start for a second then choke out. Kill switch is not an issue if you have spark.

 

[wadeatl]

Thanks RCO ... The main nozzle gasket is there. Compression is 95 on both cylinders. Coils were not cracked and worked perfectly on the previous engine before it overheated. The front coil is on the top cylinder. When you say the the mouse nests were in the exhaust ... was that down in the the mid section? I looked all the up from the LU and it was all clear..

 

[tomhath]

Do you still have a good spark after swapping the ignition? Did you also check that the spark plugs are firing? If yes to both I'd check the carb to ensure the float isn't stuck.

 

[AlTn]

certain that the float is installed correctly?..the tab on the float arm where the pivot pin goes through should point towards the carb body, not the float bowl.

 

[bwkre]

I have a 61, 18hp that I just woke up from it's winter nap. It was fogged & had fuel stabilizer added last fall and choked out till it wouldn't start again. All the fuel gone. Couple shots of fogging oil in the plug holes and off to sleep.

So yesterday I got the unit out and in the tub for the first start to burn off all that oil. Started on the second pull & died. Started up again and smoked for a good ten minutes. As it was running I got my timing light setup to check the timing. Top cylinder was advanced a little too far so I figured now would be the perfect time to correct it.
But you think I could get that motor to start again! No way, didn't matter what I did and I couldn't figure out WHAT I DID. I spent near an hour fighting that motor and it wouldn't even cough. Lots of fuel, great spark, it should have run.
Eventually I decided to go get a brand new set of plugs. Set the gap, installed them, and she fired right up as if nothing was ever wrong. I'm finally beginning to believe it, as my brother told me, spark under compression is not the same as spark in open air. I think that's why the guys here always ask for the use of a gap tester and to listen for the snap sound.

I would suggest you try a new set of plugs. You may be surprised by the results.Nothing worse than a fouled plug to throw you off.