93 Johnson 150 - RPM/Compression

[tlove]

Just purchased used 93 Stratos 274DC with Johnson 150. Seller didn't have any original manuals. I will be purchasing at least owners manual on motor but have a couple of questions until I get it.<br /><br />What is normal compression for this engine. I tested prior to purchase only looking at difference between holes. High reading 91, low reading 88. I was happy with a 3lb range but would like to know what normal reading is.<br /><br />What is the recommended RPM operating range and WOT RPM.<br /><br />Thanks!

 

[Hooty]

Re: 93 Johnson 150 - RPM/Compression

Compression looks a little low but, as you noted, there all within 15 psi high to low and that's what's important. The numbers can be made to come up. The maximum rpm for that engine is gonna be in the 52 - 5700rpm range. <br /><br />c/6<br /><br />Hooty

 

[adam171771]

Re: 93 Johnson 150 - RPM/Compression

I understood those 1990's Johnson loopers had low compression, it is the way it is designed from factory. 88 - 91 would be excellent in that case.