Max RPM / timing for stock 92 200hp merc

**MercRoy** · 04-19-2019, 05:11 PM

Hey all love these forums
got a quick question what RPM is safe for my merc as long as I ensure fuel and ignition stay strong

i will be installing velocity stacks and tuned exhaust here shortly

**Merc 2.5** · 04-19-2019, 06:30 PM

Well 1st of all, u need rejet using stacks, and make sure black boxes off and throwed away and timin set 23*, make sure u do ur homework b4 starting mods , if never done it can quickly ruin a good motor, 6000-6200 and will last

**Motv18** · 04-19-2019, 10:41 PM

Will definitely need to know some number to see if your plastic or steel bearings.

**MercRoy** · 04-20-2019, 01:12 AM

OD115252

is the serial number

**Merc 2.5** · 04-20-2019, 01:43 PM

Looks to be steel cage , not 100 percent but from looks of parts diagram , 1 mod needs another mod ,needs another mod , for the motor to run like suppose to and not lean it out.

**MercRoy** · 04-24-2019, 11:47 AM

Any idea of how many jet sizes I should increase as a starting point with stacks and the tuned exhaust

**Merc 2.5** · 04-24-2019, 07:02 PM

Well 1st thing , I can't believe race man hadn't said anything bout ur "tuned" exhaust , what exactly did u do to tuner ?? Usually show absolutely no increase in power , plain ole 2.4 bell tuna or a Bob's 2.5 tuner is ur best bet , but tuner requires no jetting but removing air box for stacks , I'd go up least 2 sizes and do throttle chop. What's the compression?

**MercRoy** · 04-24-2019, 07:12 PM

It is stock compression for a 92 200hp. the exhaust and stacks are from bobs

**Merc 2.5** · 04-25-2019, 02:31 PM

Ya 2 sizes up should b fine. wont notice nething from tuna ,wont notice anything from stacks , but since it is takin in more air need more fuel, stock fishin mota kinda fat start with and sum dont even rejet ,but jets get expensive. start 2 up , more end up with 1 size up

**MercRoy** · 04-25-2019, 03:08 PM

Awesome thanks for the input appreciate everyone time

**MercRoy** · 05-14-2019, 05:27 PM

Getting ready to set timing on this engine. Many forums on this site say to remove low/high spark advance permanently and set wot timing at 25 degrees
good advice? And do I remove the idle stabilizer box as well?

**FORBESAUTO** · 05-14-2019, 09:28 PM

Yes, remove all boxes except switchboxes. Without indexing flywheel on all six cylinders so you can check each cylinder and set highest running cylinder to 25, I wouldn’t go above 23. To index it, you’ll need a dial indicator set up through spark plug hole, or order the JSRE TDC gauge ( for the money and ease of having what you need, it’s hard to beat). We have a thread on here explaining how to do it.