1968 Johnson 9.5hp Acceleration Issue

[sabeadle]

Hello Everyone,

I have a 1968 Johnson 9.5hp, Model#: MQ-14E

Last year I had it on the water after years of sitting in the shed. It took a while to start but I eventually got it going. The issue I noticed right away is that there is no acceleration. I turn the throttle and there is no response beyond the minimal idle speed. We are back to summer here in Canada and I would like to get the motor running like normal. I haven't tested it on the water yet this year.

Some info:

• I tested the Compression on the two cylinders yesterday after I was graciously suggested to do so on another forum. Both are at 60PSI

• I bought two new spark plugs. Tested them yesterday as well by keeping it in the boot and resting it on the metal of the engine. I got a strong blue spark.

• Another point I am not sure is relevant. I did get the engine to go full throttle on the water twice last year after I ran a bit of seafoam in it. I am not sure if i used enough. But after I lowered the throttle it would not work past an idle speed.

Any suggestions as to where I can go from here? the motor has sat for a long time and am not sure if that is the issue in itself.

Thank you,


Spencer

 

[oldboat1]

Let's just say for now you have adequate compression and spark.

Run clean gas and 2-cycle oil mixed at 50:1. Use a clean tank and hose, or borrow one. SeaFoam just confuses issues for you.

If you have compression, spark and clean fuel, you should be good to go. If not, your carburetor needs cleaning.

Change the oil in the lower unit as you mentioned somewhere, and change the impeller. Check the prop to make sure it's going to speed up if engine rpm increase.

 

[sabeadle]

I really appreciate that response. I will be able to get in the water mid week and will attempt everything you suggested.

I ordered a carb rebuild kit and am going to attempt that as well which will give me the opportunity to do a good cleaning I would imagine. The motor sat many years so I am trying to cover bases before going on the water again

If I still have problems I will definitely update the post.

Thank you