1984 Mercruiser 470

[maverick325]

I have a 1984 Mercruiser 470 170 HP 3.7 inline 4. not sure about the outdrive model at WOT I get around 4900-5000 rpm i have a 19 pitch prop not sure about the diameter. I found a website that has some info about my engine and it says that at WOT the Max RPM should be from 3800 to 4200 rpm i don't have a manual yet to double check it. Can anyone tell me litle more about the engine(should I keep it or should i get rid of it) as far as i know it has updated camshaft bearings (steel type)what i have seen from previous posts that was one of the problems tough it still has the original battery charging system. And the other question is what should i do about the max rpm range the boat does around 40 mph the prop isn't in the best shape I might have to replace it anyways (should i go to different pitch and if any suggestions what pitch) I know I ask a lot of questions but i hope i get some answers. Thanks in advance...

 

[Trent]

Re: 1984 Mercruiser 470

The RPM range is 3800-4200.<br /><br />For every one degree pitch change is equal to 200 RPM (rule of thumb). You are underpropped. I personally would go to a 21 pitch and give her a try.<br /><br />Also check the tach to make sure its correct.<br /><br />If your charging system goes out; Replace it with an add on system. Also the waterpump on these leak over time. You will have to replace the two seals around the camshaft to repair.