difference between 175 and 200?

[Banana Boat]

what is the difference between a 1987 175 and say a 1988 or 1987 200 hp?.can i make the 175 a 200 without too much trouble?.thanks

[vector mike]

I'm not possitive but I think it is the exhaust plate and the carbs.

[Jay Smith]

Banana Boat ,

Also most 175's have an exhaust relief slot in the sleeve above the exhaust port that relieves compression a bit early to improve idling . Compression is lost out this slot early and hinders compression to be contained and performance to be made ! The 200 motor has the conventional sleeve.... and be hopped up with ease. The 175 can be bumped a little but to to the extent the 200 can....

Good luck and good boating,

[Doubledog]

Merc/OMC?

Don't want to ASSuME anything:D , but I'm thinking you're talking Merc. Would that apply to the OMC's also? Thanks

[dangerousd]

I was wondering if there is much difference between a 1985 2.4L 150 and 175 motor? Assuming we are comparing apples to apples and both have the exhaust relief slots, do they simply change the performance via carbs and jetting or exhaust tuners or is there usually always small port timing variations?

One of the guys in my fishing club thinks that simply jetting up on his carbs may be the difference on his 150 vs 175 Merc of that era, but I assumed there may be slight port timing variations, but don't know who to ask to find out for sure as I'm sure it varies from year to year on how they derived the HP.

Thanks for your thoughts.

[JamesE]

The relief slot you talking about sounds similar to the little pin hole above the exhaust port in my 3.0L Johnrude. Am I correct in this assumption? How much would performance be affected if this little hole were plugged and what is the best way to do this?

[Dave S]

What are you doing in Germany? Are you watching the BMW's and the Mercedes to make sure that they don't use Mercury parts? Just kidding:D . What is that prop you have on your opening page? It looks like an old Merc prop, but they don't have solid hubs, do they? Anyway, 175 Mercs have smaller jets and a straight exhaust tuner megaphone, like a150. It also has 150 style vertical reeds. The block seems to be the same as the 200. The 150 XR2 is the opposite way, using a 200 tuner and bigger reeds and a 200 exhaust plate. Mercury played around with all these parts. Were they jerking us? Or did they know what they were doing?:rolleyes: Horse power ratings all over.:p

[jerry]

about 25 !!!!!!!!!