RS34 Tuning Assistance Please

Groovy Daveo!! Has your oil consumption dropped? 400miles per quart is Waaay excessive, is it falling out? Baffle doesn't resemble an oil burner.

17.5 pilot jets and fuel screw adjustments have improved the spark plug color uniformity considerably:

 

...and non-ethanol 90 ⛽️ 

😊

To address oil consumption, I let the T4 engine oil drip out of the motor for the past two days.
I'll return the new jug of T4 bought Saturday, and carefully pour a gallon of T6 in the motor instead.

Could someone advise me which T6 Rotella will be better for my motor, given the choice of 5W-40 or 15W-40?

Tough decision to make this change, but the results of changing fuel is making it a good bit easier.

😉
 
200    200+   190+   200+

Personally I would go with the 15w-40. These old motors weren't designed to run on thin oils and it may improve your consumption.

Wookie58 wrote:

Personally I would go with the 15w-40. These old motors weren't designed to run on thin oils and it may improve your consumption.

+1