1954 25hp no spark

[dtsman]

Re: 1954 25hp no spark

Yes I have been through the carb. Carb kit, tested float.

Rented a pressure checker. Both cylinders show less than 30psi. Is that even possible to be that low?
Am I doing it right?

I am going to be out around $100 in electrical upgrades because the guy that sold it to me told me it had good compression. The compression seems so good, I can't use the pull cord. I can pull the pull cord with no plugs in it.

Also, I did the fuel pump upgrade per directions in another thread. While I had the carb off the motor, I removed the cover assembly behind it, where the pressure line for the tank hooked up. I removed the double flapper check valve thing and plugged the left hole. Could this be the cause of low compression?

Bo

 

[kfa4303]

Re: 1954 25hp no spark

HI dtsman. Glad you got it running, if only for a short time. That means the compression is probably ok. The 30 psi is NOT accurate. Your motor wouldn't run if that's all the comp it was making. Make sure that the tester is completely threaded into the s'plug socket and remove the other spark plug as well. This will allow you to pull the motor over with ease. 6-7 pulls should be enough to give you a good reading. Then repeat the procedure on the other cylinder. However, the fact that it runs means that compression is probably not your biggest issue. It sounds like you've got spark, and compression so we should focus on fuel delivery. What type of fuel pump did you buy to do your conversion with? How did you adjust your carb needles?

 

[HighTrim]

Re: 1954 25hp no spark

If he cant get it started now compression may very well be a factor in my humble opinion.

I would stick to verifying compression first, and go from there. Beg, borrow or steal another meter and see what you get. IF you still have the 30psi, you found your issue. Time to open the head.

 

[dtsman]

Re: 1954 25hp no spark

I find it odd that they are both at 27psi. There may me a shared issue. But this is my first outboard motor, and not sure if tearing it apart is best just yet.
I tried it with both plugs out and with the other plug in, in case the gasket was leaking between cylinders.

I will take a step back, and determine how much more I want to put into it.

Thanks everyone.
Bo

 

[Chinewalker]

Re: 1954 25hp no spark

I would try the gauge on another motor, maybe a mower or something, and see if it may be the issue...

 

[jasper60103]

Re: 1954 25hp no spark

..
Rented a pressure checker. Both cylinders show less than 30psi. Is that even possible to be that low?
Am I doing it right?

...

I don't think you need to use that adapter. Screw in the tester snug against the rubber o-ring.

 

[1946Zephyr]

Re: 1954 25hp no spark

That's a pretty nice motor. I can't believe that there would be any problem with the compression. I can't see any discoloration on the head, so it does not appear to ever been overheated. I would just run it. Try another compression guage, after you run it for a while. That will get the rings loosened up and fresh fuel mix around them.

Nice looking old motor.