This Dolmar 4-cycle backpack blower (model # PB-7601.4) runs on straight gas...so no 2-stroke oil is needed. The sump has a volume of ~7.4oz with an initial break-in oil change at 20hrs, then every 50hrs. Like most handhelds, there's no hour meter...so I'm quite sure I'll be changing it more often than is recommended. I paid $400 -> tax not included. This is my 2nd BP blower...the other is a RedMax 8001, used since '09 I believe. I'm a big proponent of quality 2-stroke oil (Stihl Ultra) mixed into ethanol-free premium (91 octane) fuel. The RM8001 is still running strong, VERY strong. The Dolmar engine is manufactured by Makita Numazu. It is exactly the same displacement as RedMax current big boy's 8500 at 75.6cc...though the RM is rated at 4.43 hp while the Dolmar is rated at 3.8 hp. I fully realize my 8001 is no 8500 in terms of power, but it certainly moves a LOT of air. Dolmar vs RedMax 8001: First off, the Dolmar is lighter by a couple pounds at least...and I'll estimate that the entire blower casing is 3/4s the size of my RM8001 in nearly all dimensions. The Dolmar is much more comfortable to put on and wear/operate...mainly because there is less back fatigue due to the unit's weight being closer to the body requiring less leverage to hold it up. Powerwise, I'll say the RedMax moves more air...and is definitely louder while doing so. The Dolmar does not move the same volume of air, but due to its slightly narrower tube opening it feels and looks like it is more efficient at dislodging items in cracks as well as grass stuck to concrete. In the short time I've been using this Dolmar, it has gained more power most likely due to engine break-in. It is also quieter, but not by a huge margin. It is more than capable of my daily solo route of mow-trim-blow-go. Like I said, it moves the debris differently than my RedMax...I'm even coming to the conclusion that it moves debris from a farther distance better than my 8001. Perhaps this has to do with mph of the air leaving the tube? Since I don't readily know the specs of my old RM8001 I can't say for sure. But I will speculate that the numbers on the Dolmar may be conservatively rated. Ease of starting: This Dolmar is a BREEZE to start. 2 pulls in the morning...first with choke on, the second with choke off...and it is ready to go! One pull the rest of the day with the choke off is all it takes...period. Full power in nearly immediately at your fingertips in the AM...and she is GTG the rest of the day upon restart. Ease of use: While my RM8001 has a separate hip throttle on the left side, this Dolmar has a tube mounted throttle with a separate finger-operated cruise control lever for optional continuous use overiding the spring loaded trigger throttle. Future: I'll give this blower a proper workout come Autumn leaf time...and compare directly with the RM8001. At this point I'll guess that large piles will be easier for the RM...but this is several months away and I'll report back then. 2-stroke backups are a Stihl FS-80r and the above mentioned RM8001. Both start & run very well and I've been pleased with their reliability & performance. The Stihl did require a new ignition module, but that is it b/tw the two as far as parts replacement......other than routine maintenance items. Conclusion: Yep, I'm very impressed. In my quest of operating w/o mixed gas during the workday, this Dolmar 4-cycle blower definitely compliments my recently purchased Honda 4-cycle 35cc trimmer. Both only require regular unleaded (86 octane)...so even though I use only ethanol-free fuel for my equip, this will save money over buying premium -> while eliminating the need to purchase 2-stroke oil. So in essence, this Dolmar blower AND my Honda trimmer have already begun to pay for themselves. These 4 cycle HHs are both quieter than their 2-stroke counterparts, the trimmer especially...and there is no 2-stroke oil odor on/for me, for my customers...and for my customer's neighbors to inhale/smell. So, I figure I'm doing myself a favor (pollution-wise) in this process of switching to 4-cycle handheld equipment.