Hi All. I brought my 25hp motor back from my cabins last fall to try and address an apparent low power issue in the off season. I still have some time before I am wanting to use it.
The model number is J25TEETS. I run it with a 10.5x11 prop. I switched from a 13 pitch down to the 11 as I was running the boat heavy for long/far trips out on the lake. When I made the switch to the 11 pitch prop I could still get up closer to 19mph or so. Now I'm down around 15-17.
I checked compression and both cylinders are around 120 with the gauge I have (I know it is old, I am not sure of the accuracy of the gauge, either). The check was done without firing the engine. I pulled a spark plug, pressed the gauge in the plug hole, and ran the starter. The motor has been sitting since September not having run (it does run though).
My thought when I brought it back home was the compression was low. 120 doesn't sound very low to me, however I do not know what it should be or what it was before. I presume there is some blow-by past the piston rings, but again - 120 doesn't tell me this is too much of an issue, I don't think.
So I guess I am a bit lost. I put brand new plugs in it last summer. I was having problems with the engine idling and starting. The plugs resolved those issues. However, it still feels too low on power. I have adjusted the throttle linkages and carb. I can't see adjusting anything else on the engine to get any more power out of it.
If the compression isn't terrible I'd rather leave it be than to tear the engine apart. What are everyones thoughts?
Thanks!
The model number is J25TEETS. I run it with a 10.5x11 prop. I switched from a 13 pitch down to the 11 as I was running the boat heavy for long/far trips out on the lake. When I made the switch to the 11 pitch prop I could still get up closer to 19mph or so. Now I'm down around 15-17.
I checked compression and both cylinders are around 120 with the gauge I have (I know it is old, I am not sure of the accuracy of the gauge, either). The check was done without firing the engine. I pulled a spark plug, pressed the gauge in the plug hole, and ran the starter. The motor has been sitting since September not having run (it does run though).
My thought when I brought it back home was the compression was low. 120 doesn't sound very low to me, however I do not know what it should be or what it was before. I presume there is some blow-by past the piston rings, but again - 120 doesn't tell me this is too much of an issue, I don't think.
So I guess I am a bit lost. I put brand new plugs in it last summer. I was having problems with the engine idling and starting. The plugs resolved those issues. However, it still feels too low on power. I have adjusted the throttle linkages and carb. I can't see adjusting anything else on the engine to get any more power out of it.
If the compression isn't terrible I'd rather leave it be than to tear the engine apart. What are everyones thoughts?
Thanks!
