correct fuel?

[imported_roy]

On the valve cover of my '75 Volvo Penta 130 there is a plate that lists engine specifications such as timing, firing order, etc. One thing on this list that I am not making perfect sense of is a line that reads:

Leader gasoline of 93 ROT

Is this telling me that this engine must have a minimum of 93 octane unleaded fuel to meet specifications? And if so, will fuel with a lesser octane cause it to run rough?

 

[bjcsc]

Re: correct fuel?

My guess is it says 93 RON. If so, the answer to your question is no. The pump rating of fuel is the AKI (anti-knock index) and is an average of the RON (research octane number) and the MON (motor octane number). You'll see it on the pump (R+M/2). The RON is usually about 10pts. higher than the MON. The average RON of 87AKI fuel is 92, 89AKI is 95. So you should be using 89AKI. Using lower grade fuel without retarding the timing can not only cause an engine to run rough, it can kill it esp. if it is not equipped with a knock sensor. That said, I run premium even though technically mid-grade is all that is required.

 

[imported_roy]

Re: correct fuel?

Leader gasoline of 93 ROT

This is exactly how it reads. However I am going to dump the fuel and start over with a premium grade to see if I can get the results I'm looking for. I have been told before to check the fuel system and everything else has checked out ok. This is the one thing that I can think of that I have not checked so far. Thank you bjcsc for your help. And thanks again to Don S and Mahoney for suggesting fuel system in the past.

 

[Mahoney]

Re: correct fuel?

You should be fine with 89 octane, which is regular in my part of the country. If it runs without pinging, thats all you need, anything more is just throwing money away.

Higher octane is for high compression engines and is a detonation inhibitor, contrary to what most people think, it is not a "more powerful" gasoline.

 

[bjcsc]

Re: correct fuel?

Roy: I'm not sure what your situation is but you could try to run it from an auxillary tank (even a piece of fuel hose going into a can) before dumping the fuel (unless you are highly suspect of its condition)...

 

[imported_roy]

Re: correct fuel?

I found a new crack in a fuel line and changed the gas to super and the combo of the two fixed my lack of power. Almost got this old beast running right again. Thanks to all!!