little power 9.5hp evin 1969

[seawolf]

My 9.5hp compression readings TC 64psi BC 59psi.
Sprayed some WD -40, retested on warm motor , same readings no change.

Has little or no power from 1/2 throttle to WOT, and misses regularly like clock work every 3 seconds or so upon power up. Idles fairly well with some vibration.. seems normal.

Carb has been rebuilt and is clean. no gas leaks in hoses. brand new fuel line and connectors.

Replaced plugs and after 1.5 hours under load, see small oil spattered on outside of ring of plugs, but only on one side (same ) on each plug???

coils, condensers, and points changed and gapped 0.20 in.

plugs gapped 0.30 in. and correct Champion plugs.

Before I went to the lake , I shot some seafoam into cyl head (each plug) and sprayed a couple of good shots to the carb throat.

I think gas is coming from exhaust ( not being burnt completely ).

What should be my next course of action, remove exhaust cover and inspect rings ect ??? If the rings were stuck or broken would I be able to hear a mettalic noise like rattling or such?? If it was rings would the motor produce some smoke, and would my compression readings not increase after spraying a shot of WD??


Any suggestions woud be appreciated. Thanks ..

 

[kodibass]

Re: little power 9.5hp evin 1969

Has the motor sat for some period of time? those compression readings are low. It sounds to me that you might have a carbon problem, do a good de-carb, re clean the carb, after the de-carb clean the plugs use a known fresh gas source, re-check/set your carb high circut. If this does not improve things you should pull exhaust port cover and the head and have a look at the cylinders

 

[seawolf]

Re: little power 9.5hp evin 1969

The motor was used last summer 5 times in a 2 week period. Same sluggish power, and has only been out once this year.

The compression tests were performed in somewhat cooler weather this spring. I sprayed deep creep in the cylinder head and carb throat ran till it stalled, restarted and ran for a short time in barrell.

I just did a new compression test today and things look more promising.

68psi Top cyl and 65 Bot cyl. After a squirt or two of WD-40 Top 71psi
Bot no change or 65psi.
I realize my compression test is only somewhat accurate. I am using a 25 dollar Can tire gauge that screws in .... hardly precise I know.

Both plugs give good blue spark.

Am I on the right track.
I will decarb somemore and post the results.

 

[Daviet]

Re: little power 9.5hp evin 1969

Spark, compression and fuel is what it takes to make your engine run. Have you checked the spark with a spark checker? It should jump 3/8" and have a bright blue color.
The compression is a little low but should run on both cylinders, once you get it running properly you would need to do a good decarb.
If spark and compression check out, I would question the carb. When you cleaned the carb did you remove the core plugs and make sure the low speed circut was clean?

 

[seawolf]

Re: little power 9.5hp evin 1969

No I did not do the carb. It must have been done before I purchased the motor. It *appears* clean with a new float. The seat needle was free and the gaskets appear new.

Today I barrell tested the motor again, brought it up to temperature and
sprayed the cylinders with deep creep and blew it clean again. After 30 minutes shut down I rechecked compression Top cyl 81psi Bot 79 psi.

I can't believe the difference when I check each time.

 

[kodibass]

Re: little power 9.5hp evin 1969

I'd say your on the right track, Your compression is in the ball park, one other thing check your fuel/ vaccume lines from hose connect to carb connect and all points in-between, It almost sounds like a air leak/suction thing might be going on, point is you won't be looking for a fuel leak, you'll be looking for a air leak, in the fuel system. What makes me suspect is that your problem is 1/2 to wot. this could be your engine sucking to much air in and disrupting your fuel flow from the tank. good luck. KB