Compression on 1988 70 hp evinrude

[Tonja]

What is the compression supposed to be on a 1988 70 hp Evinrude. Also what is to low.

 

[DJ]

Re: Compression on 1988 70 hp evinrude

Tonja,<br /><br />It should be over 100 psi. More importantly, all the cylinders should read within 5-10% of each other.

 

[G DANE]

Re: Compression on 1988 70 hp evinrude

Hi Tonja<br /><br />Djohns19 is perfectly correct, above 100 and equal is what the manual states.<br /><br />However most of the motors I worked on, Johnson and Evinrude from that vintages, showed compression between 125 and 145. This will give you an idea of the motors wear too. Some v6 however have lower compression from factory.<br /><br />I Exa I have a 40HP 1988 that has 145 and 148, and my 115HP 1991 has 128 128 128 135.

 

[Tonja]

Re: Compression on 1988 70 hp evinrude

Thanks, I am checking it in the morning and will let you know what I find....It has been bogging down like its running out of gas after 4000 rpms.

 

[Deuce22]

Re: Compression on 1988 70 hp evinrude

TonJa,<br />I just did my compression check last night on my 83' 70 hp Rude, and they all read right around 135psi. The mechanic that was giving me a hand said that was really good. I was also bogging down under a load. We dismantled the carbs for cleaning and we are going to install all new carb kits. Hopefully that will do the trick.<br />Good Luck<br />Deuce