Is my Mercury ready for the scrap yard or will it live a little longer?

My Mercury 1984 75HP serial number 6559264.

Compression reading are
1- 95
2- 95
3-90
4-85

Here is what has been replaced. Spark plugs, trigger, impeller, lower end oil, carb kits on both carbs. Stator tested bad but not replaced yet.

My engine runs and idles on the hose, in the lake it idles but in forward gear it will not get over 15 to 1800 RPM’s . Before I spend more money and time putting on a stator will this fix this issue or am I completely out of luck because of the compression readings?

I still needed to replace crumbling wiring and interior fuel lines before I solved that problem and yes I got a big boost in power from replacing the stator. Your compression seems too low but that could be the gauge. Borrow another from auto zone and see what it is. Mine was much older( 78 50) but runs hard after spending more than !/2 grand on it.

Too much prop?

Jeff

You might try fogging all the cylinders really well "Seafoam Deep Creep". Turn the motor over for about a minute to spread it around and fog it again. Then let it sit for a couple of days. The "Deep Creep" will help dissolve carbon buildup and loosen any stuck rings. Then try your compression test again.

If it has done any good your compression reading will rise. Four is a little low but just slightly out of the magic 10% acceptable deviation.

All the others are OK, not great. Your motor is 35 years old. Assuming it has been used with some regularity it is doing well.

If your '84 Merc is anything like my '85 - 60hp. I would replace the stator and most all the wires, including the plug wires. It is time consuming, but not hard work. It probably has another 10 years in it.

Fish...On...

Pleasantman said:

Update: I changed the CDI switchbox and stator yesterday. Took it out today and it ran perfectly. Did another compression test with a different gauge and got 90PSI on all cylinders except the last one was 92.Thank you everyone for your help.

Click to expand...

Thanks a whole lot for getting back. Always good to hear a success story.

Glad you revived your car.

Glad you revived your car. I am hoping to be able to do the same with my own mercury. I have been shopping for second hand parts lately. I got the most part from scrapi.com. I was thinking about ebay at first but the prices were too high and I would have had to go way above the budget that's why I went for a scrap yard. You'd be surprised for the quality you might get for the price they are charging. It has already become something like a hobby of mine - trying to restore cars with parts taken from scrap yards only.