Mercury 150

Dan · 02-08-2005, 09:39 PM

Couple of questions. What (economical) changes can you make to get as much as poss out of a Merc 150 Blackmax, ie swapping carbs etc etc.
Also would this be a 2ltr or a 2.4ltr engine, its a 1990.
Thanks

JamesM · 02-08-2005, 09:45 PM

The 150 does have smaller carbs but I think the main difference between the 150 and the 200 is in the ports, particularly the exhaust ports. So no big gains really unless your any good at port work.

MrRob · 02-08-2005, 09:50 PM

its the same motor I had dan. Its a 2ltr and I thought of tuning it up but in the end I sold it and bought the 225promax. The the cheapest easiest way!
I might sell that next year and go for a 2.5 racing engine in the 300hp range but I doubt I will! 70+mph its good enough for me!

JamesM · 02-08-2005, 10:02 PM

Yep just had a look at S and F and I'm pretty sure its a 2.0litre. The 2.4 150 was called an XR4 and the XR6 150 was a 2.5.

Dan · 02-08-2005, 10:15 PM

Quote:

Originally posted by Johnny Boat Dude
The 150 does have smaller carbs but I think the main difference between the 150 and the 200 is in the ports, particularly the exhaust ports. So no big gains really unless your any good at port work.

What gains would I get then by chaning the carbs and what carbs should I be on the look out for?

JamesM · 02-08-2005, 10:18 PM

not alot to be honest you may even loose power unless you jetted em right. Jetting would be a pain too as what do you use as a reference and can you read piston tops?

MrRob · 02-08-2005, 10:24 PM

sell it and buy a new engine!

JamesM · 02-08-2005, 10:35 PM

For some small gains you could remove the exhaust can from the midsection possibly fit a 200 tuner as I believe the 150 one may be designed to restrict power and also remove the airbox. If you remove the airbox then either get velocity stacks or an intake plate like the one pictured or make one by cutting up the discarded airbox. The bare carbs don't flow much more air than an airbox as the flow is turbulent due to the sharp leading edges of the carbs.

If you do this jet up 2 sizes ie. 64' to 68's.

JamesM · 02-08-2005, 10:37 PM

Notice the sharp edges on the intake of Burty's old airbox off'd 2.4 without the intake plate.

Dan · 02-08-2005, 10:57 PM

JBD, so by the sounds of it its alot of messing around for not to much end results then. Oh, well guess it will do for the time being then, stick a after market cowling on at some stage and at least it will all looks the dogs.
Cheers