2.5 Spark Plugs

[MUDSHARK]

What is the best brand of plugs to run in my 2.5 200 carb motor? It is a 93 model and has 115lbs comp.

[Jay Smith]

I'd use an NGK BUHW....( surface gapped plug )

Jay

[MUDSHARK]

I would also lke to upgrade to better reeds, rany advice on if I should jet the cabs diff it if i go with another reed setup?

[Jay Smith]

I use the TDR reeds in every motor I build from race to recreational with GREAT results... I keep them in stock for most Mercury engines.

Most of the time jetting is OK stock IF your in a humid hot location...But if your concerned a 1 set up in the main would be safe with super ...

Jay

[MUDSHARK]

Thanks for the input. I will try a set of those in my XR4 back up motor. I already ordered a set of Boysen Reeds this morning for the 2.5. I live in Fl so it is a hot humid environment but I was told by a Tech from Boysen that they might make the eng run lean at low speeds. Most of my running is done at rpms over 5000 and up to 6900 with a top speed of 85mph on a Hydrostream YT V King. If I leave the jets stock will I be in danger of a melt down or should I change the main jets. I would also like to know if Its safe for me to run 100LL AV GAS? Or would I get better results with pump gas? Eng only runs 115 lbs compression. Its not a racing motor but I run it pretty hard and want to get the best results for this application.

[MUDSHARK]

After checking the serial number today I was told the eng. should be a 96 model and not a 93. Serial number is OG396835. The plugs that I have been using are B9HS10. I ordered Boysen reed part number 26413 for it. It has velocity stacks and the carbs are marked as 2 WMH. Thanks alot.

[Jay Smith]

With 115 lbs cranking @ sea level I don't think you have a worry with super unleaded..

Jay

[T-REX]

I have a 2.4 Bridge port carb'd mota wit 120#s ov compression...I run tha BR9HS-10 in it, and use REGULAR gas.....I put tha puss heds on it so I could run regular gas, kuz it's a river mota...It'z a river mota, but still turns a 28" cleaver 7600 rpm(so for)...I have never streched it out, still gitt'in used to tha boat!!....Tha mota haz turn'd 8600 on my 16' laser with a 26" yamaha wheel...ON REGULAR gas!!

[MUDSHARK]

The main reason I asked about 100LL is because I've been told that it has no ethanol. At least at the airport I work at does not use ethanol in it. It's not much more than premium pump gas and way cheaper than sunoco race fuel. Just dint like the gas station and I never trust that they are selling a good product. At least with the av gas I know it is strictly regulated by the FAA and if it says 100 octane you know that's what ur getting. But with a motor with such low compression will the 100ll hurt it in any way. I know the motor won't last forever I just want to know while I'm raping it that I'm using the best oil and gas and plugs and reeds. Never been more proud than when I windowed my first 2.4. Completely came apart after three years of hard use and I had boysen reeds in it and I ran alot of 100ll. Always have used Klotz synthetic and mixed 40:1 for a easy ride and 32:1 if I was goin to really stretch it. I'm not saying I know exactly what is best for any motor just wondering if I was doin anything wrong with my set up.

[T-REX]

Tha hiogher octain juss won't burn az good wit low compression....it won't hurt nutt'in, juss won't maximize ya HP wit ya combo....

I tested tha theory ov Premium(93octain) vs regular(87octain) with a stockie 200, 2.5, 115#s comp...I had 2 tanks in my 380 Laser, one with 93, and one wit 87(both were mix'd 40:1 merc prem blend).....Tha mota turn'd 6500 with tha prem, and a swap ov tha tank, tha mota turn'd 6900!!!....Simple test......I ran that mota 13miles @ WOT wit no problemz.....,.Now, that wuz several yeerz ago, and ethanol wuz not a factor!!!!

[Jay Smith]

What the "Ole Fart" said is correct , if you over octane a 2 cycle it WILL hinder power.. Fact is 87 octane makes GREAT power BUT also make great heat to boot. It has a VERY fast burn rate and will not support allot of compression without heating the piston crown to a point it WILL ignite the oncoming fuel vapor charge well before ignition should occur causing detonation and blown up engines . 99% of most outboards don't have the luxury of an ignition that retards timing due to low octane fuels as cars do. As long as you support the compression with the correct amount of octane to cool the piston crown your OK, if you over kill with too high an octane its safe but lazy and expensive if you under estimate the needed octane say BYE BYE to the pistons..

At sea level at a WOT at 25 degrees and 115 ish compression Super Unleaded is totally safe..A dime more a gallon is cheaper than pistons and the pain in the kester of being broke and time off the water IMO..


my .02
Jay