omc sterndrive/ford302

[robert r]

hello i'm robert, i have a 1977 formula thunderbird omc 175 hp the help i need is i don't know what the rated rmp should be so i don't know what pitch to use? on the lake i went to 4500rpm and got 30mph but i could open it more i stoped at 5500rpm did not want to hurt any thing. can anyone help robert

 

[tommays]

Re: omc sterndrive/ford302

I would check the tack against a shop tack first at 30 years old i would not have a lot of trust in it with out checking

Somebody should no the exact RPM BUT around 4400 ?


Tommays

 

[Boomyal]

Re: omc sterndrive/ford302

I would check the tack against a shop tack first at 30 years old i would not have a lot of trust in it with out checking

Somebody should no the exact RPM BUT around 4400 ?

I'd say 4600 for cruise WOT or 4800 for pulling WOT. 5500 is way too hot. That little 302 'd be puking it's guts out running under load at that rpm.

 

[NW Redneck]

Re: omc sterndrive/ford302

Waaaaayyyyyyyy too high!!!!

From the OMC 175 owners manual:

Displacement: 302 CI
Bore and stroke: 4.00 X 3.00"
Firing Order: 15426378
Full throttle oerating range: 3800-4200 RPM
Idle RPM: 500-600 RPM

I have one too! Mine's a 1975 vintage. A cheeky little number with a great 'nose'. d Definitely check your RPM's with a known guage or an automotive DMM with an inductive pickup. If your RPM's are as you say, I think you either have some serious throttle/carb adjustment problems, or you need to go way up in pitch.

Once you have an accurate RPM reading, see what pitch/diameter your current prop is and post in the prop forum. Smart guys over there, but they need accurate info to be any help. (And they'll make sure you know that! :devil:d)

Let me know if you need any more specs. I have the small owners manual, and a Glenn's shop manual that's not bad.

Good Luck!

 

[robert r]

Re: omc sterndrive/ford302

thank you all for your help i will take all your advise, i'm going to get a new gage thank you all once more robert