78 Evinrude 175 Octane Issue

[snagroms]

I've been reading thru several posts about ocatane and motors. I'm not trying to stir the pot but get some clarification. Most posts say to use 87 octane and correct oil TCW3. However, was digging thru my new manual (Evinrude Service) and it recommends 89 octance. Would you follow the book (probably) or have there been enough changes since 78 that allow for 87 octane to work fine? It's not that I would try and be cheap at the expense of the motor but the price of fuel today is kinda pricey .<br /><br /><br />Than,s

 

[Dhadley]

Re: 78 Evinrude 175 Octane Issue

Fuel changes at least once a year. Its changed a ton since 78. <br /><br />With a stock recreational motor 87 is fine. And stock means the correct plugs with everything else running and working as produced.<br /><br />You can run 89 but the combustion temps will be slightly higher.

 

[snagroms]

Re: 78 Evinrude 175 Octane Issue

Dhadley,<br /><br />Thanks, Purely recreational use boat. New gas 87 octane, synthetic tcw3 @ 50:1 and champion plugs QL77J4C at .030. Book shows UL77V as recommended. Believe those are surface gap and don't have a good feel for them. iboat forum recommended the 77J4C's before I got the manual. Any real difference Temp, clearance, performance with them?

 

[Dhadley]

Re: 78 Evinrude 175 Octane Issue

I've always ran the (Q)L77JC4's in all my crossflows. Never had a problem of any kind.

 

[snagroms]

Re: 78 Evinrude 175 Octane Issue

Dhadley<br /><br />Thanks again. Your help is always appreciated.

 

[Dhadley]

Re: 78 Evinrude 175 Octane Issue

Youre very welcome!