1971 Mercury 650 Revival

[keagernaught]

I have a 4 cyl 1971 Merc 650. I have a new controller spliced into the old 7 pin harness. I replaced the fuel pump diaphragm and I noticed there is a hook up on the engine for a second fuel pump. The engine has the 1 fuel pumped spliced to both carburetors. I cannot get the motor to turn over, and I was wondering if it was related to only having 1 fuel pump or do I need to check the ignition system, or carburetor vacuum more thoroughly. The engine turns over smoothly, and has compression.

 

[jimmbo]

I cannot get the motor to turn over, The engine turns over smoothly, and has compression.

Which is it? In one Sentence it doesn't turn over, then a couple of Sentences later, it turns over?

An engine needs Fuel, Compression and Spark at the right time for it to run. If it won't start, then those need to be checked.
The spark needs to be able to jump a 5/16" gap.
Is fuel getting to the carbs?
Are you using the choke?
Regarding your concern about a second fuel pump. Are you just seeing the mounting spot on the Black/transfer passage cover, or is there an actual pump or part of a pump mounted but not plumbed in?

 

[racerone]

What controller did you use ?-----Not all ignition ( spark ) systems are wired the same.-----Some are open to run and some are closed.

 

[keagernaught]

Haha. Yea. Doesn't make since when I re-read my own post. I should have said the motor cycles just fine but does not turn over. I need to add a picture, but it is the 2 carburetor/4 cylinder design and I 100% only have 1 fuel pump leading into both carburetors. I think my problem is that I don't have spark, or that I don't have vacuum pulling the fuel into the carburetors. I am going to pull the carburetors as the next step.
racerone It is an offbrand aftermarket controller that is built for the 8 pin harness. I spliced all available wires following a diagram I found on iboats.com. I think I have the controller properly installed but I noticed the shift cables are incredibly stiff, and I am considering buying new cables or just lubricating the old cables.

 

[GA_Boater]

I should have said the motor cycles just fine but does not turn over.

Better reread your 2nd post.

Suggested rewrite - Motor cranks with starter but doesn't start.


Check for spark before messing with anything else. What brand and model is the control? Also the motor serial number?

And welcome aboard.

 

[merc850]

We really need the serial Nr. here's the wiring for a 4 cyl. 650 with Thunderbolt ignition. The red and white wires on the switchbox (left) are the energizers, red for power all the time and white for run power.

 

[keagernaught]

SN 2870xxx

 

[merc850]

SN 2870xxx what are the last 3 Nrs.?

 

[The Force power]

SN 2870xxx

Wow!! do you want help?? or not!!
Show some respect by providing as much correct information as possible, people on here are to help their fellow boaters; not to solve mysteries like what you possibly mean with cycles ?

 

[keagernaught]

2870742. My mistake. I did not realize the last 3 numbers had significance.

 

[merc850]

The wiring diagram I posted is correct you should have +12v on the red and white terminals (4 terminal side) when the key is on - as for the cables the problem might be in the box it's a good idea to take them apart every 10 yrs. and grease the components. The cables have to have some slack loop or they bind.

 

[keagernaught]

merc850 Thank you. I got it wired up properly based on your diagram. I am moving onto the fuel system now to narrow down my starting problem.