trouble shooting two problems

[rayc8]

question #1. I have a 470 mercuiser, it runs great for about 30 minutes then it slowely looses oil pressure and then starts missing then eventually dies. after about 30-40 minutes of cooling off it will re-start with good oil pressure. the boat tempature does not over heat. it runs at about 145 degrees so its not over heating.....this is what i have done to find the problem, put the correct heavy duty oil in it, replaced the cap, plugs, wires, points, coil, condenser, rebuild the carb, cleaned out the gas tank and lines, replaced the fuel pump and put a new control module on it. and i am still having this problem. the only thing i have not done is set the timming but, it runs like a champ for the first 30 minutes. does anyone have an idea of what this might be?


the second problem, while test driving it this weekend, i lost my drive, i thought i lost my prop but it is still there. the boat will not go into forward or reverse.

if anyone could help me i would appreciate it greatly.

thanks, ray

 

[Eric 3.7LX Alpha 1]

Re: trouble shooting two problems

Welcome!

I don't think the oil pressure is causing the engine to stall out. If the pressure was low enough to do that, you would hear the lifters clatter due to lack of oil. If the lifters do not "clatter" at idle, there is sufficient volume of oil to lubricate all internal moving parts properly.(from the service manual)

These engines don't have a low oil cut off switch. It says engine must have minimum of 15-psi at 2000 RPM's

You changed the points, and also mention control module? Could you please explain what the control module is?

Couple of possiblilites on the drive:
broken shift cable, damaged gears in the upper half of the outdrive, snapped vertical shaft on the lower half of the outdrive, (the last two would cause the engine to overheat if you ran it too long).

When you shift, can you see the cable at the engine move? next would be to have someone look at the shift shaft on the outdrive WHILE someone else shifts thru the gears.

Here is a picture from Ziggy, of the shift shaft on the drive. (front of drive)
Straight ahead is Forward gear