1990 mercury 150 xr4

[t_brewer]

i have a 1990 150 xr4 and i was wanting to know will putting a set of 200hp carbs give my 150 200hp

[T-REX]

No!!!

[j_martin]

i have a 1990 150 xr4 and i was wanting to know will putting a set of 200hp carbs give my 150 200hp

Like the lizard says...... It'll just fuddle up your idle.

actually, that engine with a little shavin' of the heads to up the compression from 120 to 145, chit can the advance module and time it right, and run 92 octane in it, is a purty snappy feller.

If you pay attention to LU maintenance...don't fall prey to the guys that tell you to set clearances any way but stock, Run Hi Perf lube in it, and don't beat it up grind shiftin' it. It'll last a long time, and it's skinny and slippery.

hope it helps
John

[David]

I've though of removing my timing box for years

a) What should to total timing be set to, without box?

b) What octane with stock heads?
c) What octane with cut heads?

(b) is tempting because it would allow me to go back to stock and run regular fuel again, after scaring myself once or twice going real fast.

[j_martin]

I've though of removing my timing box for years

a) What should to total timing be set to, without box?

b) What octane with stock heads?
c) What octane with cut heads?

(b) is tempting because it would allow me to go back to stock and run regular fuel again, after scaring myself once or twice going real fast.

a. 23 degrees (instead of 19)
b. 87
c. 91 - 92 @ 145 - 150 lbs compression


hope it helps
John

[David]

That does help. I hit a 6000 rpm wall with just about any prop with my XR4. 23 degrees and regular gas would suit me fine.

[props4u2]

I know some on this board don't believe this but the tuner in an xr4 & xr6 sucks for higher rpm's (above 5600 rpm's) An old style 2.4 200 XR2 or a Bob's 200 tuner along with tighter heads and 23-25 deg. timming with prem fuel sets these things on fire.


Lee

[150aintenuff]

25 degrees timing, 145 compression, 91 octain, and no modual, on stock porting will yeild about 170 hp @6000 RPM to make 200 requires #1 porting, ALOT of it, #2, a horizontal front half and intake, and carbs....

[David]

Funny you should mention the tuner. I have a G force tuner and Boyeson (sp?) reeds in my XR4.

I need to learn how to set the timing and remove that box. Then I need calm water, which I have not seen this year.

[props4u2]

25 degrees timing, 145 compression, 91 octain, and no modual, on stock porting will yeild about 170 hp @6000 RPM to make 200 requires #1 porting, ALOT of it, #2, a horizontal front half and intake, and carbs....

With all of the above (except horizontal frt 1/2) machined vertical reed cages & an xr2 tuner I have seen 190 hp on a land and sea dyno. Pretty impressive.


Lee

[j_martin]

The XR4 be a spunky motor fer shure.

John