110-120lbs
The compression ratio for a 1978 Johnson 85hp outboard motor is typically around 130 to 150 psi per cylinder when measured with a compression gauge. It's important to ensure that all cylinders have similar readings for optimal performance. If compression is significantly lower in any cylinder, it could indicate issues such as worn rings or a blown head gasket. Regular maintenance can help maintain good compression levels.
155-160 good used 170-175new
Compression testing is done on engines and it establishes whether the engine has good compression. Good compression is needed for the engine to start easily and run efficiently.
To increase compression on a Johnson 85hp outboard, you can start by ensuring that the cylinder heads are in good condition and properly torqued to specifications. You might also consider replacing the head gaskets with thinner ones to reduce the combustion chamber volume. Additionally, checking and potentially replacing rings or pistons can help improve sealing and compression. However, any modifications should be approached cautiously, as they can affect engine performance and longevity.
No, it is good in tension.
You will have to do a compression test yourself to know that. A engine that is in good shape should have at least 150 LBS. per cylinder. There can not be more then 20 LBS. difference in any cylinders. It has to have at least 100 LBS. for the cylinder to fire at an Idle.
Yes, a 1990 90HP 2-stroke L-drive boat can pull a skier, provided the boat is in good condition and properly equipped. Generally, a 90HP engine has sufficient power to tow a single skier, especially if the skier is within the recommended weight limits. It's important to ensure that the boat has the appropriate tow points and that safety measures are in place while skiing.
No, But Cave Johnson is a good one.
In the early 1970's, when you could still get good gasoline, outboard compression in the 180-190 psi range was common. If your 65 hp Johnson is running in the 100-150 psi range, this would be acceptable, and the engine should still perform well on todays fuel. The important thing to note with compression readings however, is that the difference between the highest and lowest reading, is no more than 15 psi. One more note, avoid fuels containing alcohol if at all possible.l
Good compression, good heads, good cam.
You put the compression on the fork with out a top race for the headset. Then you put on the compression cap. Next you put in the compression bolt and tighten it. Now you're good to go!
Check the spark. If that's good check compression and timing. Check the spark. If that's good check compression and timing.