'75 Mercury 650 Cyl Thunderbolt Motor

[gholmesjr]

Got a boat from a guy today, he said he was monkeyin' with it and broke some piece of plastic off the throttle actuator. Said the park was either .75 cents or 15 bucks. But I cannot for the life of me find where this part would have even been on the motor. Any ideas what this guy is talking about? I just got it home so I haven't attempted to start it. He said he was trying to get it started for me but since it was cold out and the boat was stored outside that when he was using a screw driver and the piece snapped off. It's a plastic piece. I was unable to show me where it was located. Any clues what he was talking about?

Thanks,

J.T.

 

[achris]

We're going to need to see photos of the engine, there are a lot of plastic parts on it... Photos of the carbs, and the throttle arms and where the control cable fits in to the engine....

 

[gholmesjr]

I actually was able to find where this is. Looks like I am going have to take the flywheel off in order to get to it, what a PITA. It's buried in the center of the motor.

 

[achris]

Need to know a little more about your engine. If it's a 1975, it should have a distributor on the port side of the engine. In which case there is no plastic to do with the throttle system up under the flywheel. If it does NOT have a distributor, but is 'distributorless' and just has a 3 cylinder switchbox on the starboard side, then yes, you're probably talking about the trigger assembly. That IS attached to the throttle arms and does require the flywheel to be removed to replace it. But that means it's not 1975, but a little later. A new trigger assembly is in the order of $160....

Just a word of advise on removing the flywheel. Use the proper Merc tool. DO NOT remove the screws holding the flywheel to its centre hub....

Chris.......

 

[gholmesjr]

No Title

So, the part I think I am going to need to get is number two on the diagram. It's hard to get a camera in there to take a picture of where it broke. I'm familiar with how engines work and I think what I am seeing is a distributor. Looking at the location, I could probably pull the distributor cap to get to it.

 

[achris]

Yes, that is a distributor engine, but the drawing you have is for a non-distributor engine. Here's the drawing for your engine -> http://www.boats.net/parts/search/M...BUTOR ADAPTOR AND THROTTLE LINKAGE/parts.html

The good news, the part is only 75c, and you shouldn't need to pull the flywheel off to replace it. The part that holds it in place is held in with a small screw at one end.... The bad news.... Merc don't make that part any longer (Part #38 on the drawing).... It's part number is -60575 (which supersedes to -65914, which is $11.81, but also no longer available).

Chris.....
(all the usual sites I use, and some I discovered years ago... No result...)

 

[Fun Times]

The good news, the part is only 75c, and you shouldn't need to pull the flywheel off to replace it. The part that holds it in place is held in with a small screw at one end.... The bad news.... Merc don't make that part any longer (Part #38 on the drawing).... It's part number is -60575 (which supersedes to -65914, which is $11.81, but also no longer available).

Chris.....
(all the usual sites I use, and some I discovered years ago... No result...)

Here's some other ideas for you to think about doing/trying.
http://johnsoldmercurysite.com/phpBB...php?f=7&t=4689 < Edit: You may have to copy and paste the link online to make it work.

Good luck.

 

[gholmesjr]

So, basically, I am SOL? I've called several places and no one carries them. What happens if you have an old motor and parts aren't available? I mean hell, there are old motors out there that need parts.

 

[achris]

It's not in the interest of the manufacturers to continue to supply parts for old engines. It means they don't get to sell new ones.... When parts are no longer available you do one of two things. You either find a salvage yard that may have the part, or you scrap the engine and buy something newer...

At 1975 that engine is 40 years old.... Legislation (in Australia) only requires manufacturers to carry parts for 7 years, cars 10.

Try taking it back to the guy who broken the part in the first place... If he's a nice guy he'll give you your money back...

Chris......

 

[gholmesjr]

I finally found the part on ebay. Bought the whole shifter linkage. The number stamped on the shifter linkage arm was the same part number in the diagram you gave me. So I am hoping that this will be what I need it to be. Thanks for your help guys, I will letcha know how it goes.

 

[gholmesjr]

I have installed the part. Works like it should, moves and cams the way it needs to. However, I cannot get the motor started. I have changed out the spark plugs as of tonight. I also ran a spark tester on it the other day and it lit up on all three cylinders when cranking on it. I now get a pop after cranking with the new plugs, but it will not continue past it. The starter engages and everything sounds normal. I have the cover off and I see some gas coming from the front of the carb through the butterfly valve if I continue to try and crank it, not a lot though.

With all that said, is there anything in particular I should look for or check for or something that might need to be cleaned out? Any advice is appreciated.

Thanks,

J.T.

 

[gholmesjr]

So, I've been looking the motor over. I have spark to all three cylinders. I ran a compression test on all three cylinders and all pegged out at 120, so they are consistent. I checked to see if I was getting fuel through the fuel pump and it is. I checked all the hoses and they all feel good, have good throughput. Still can't get the motor to start. The only thing I can think of now is to clean the carbs. When compression the primer bulb, should the bulb go tight? Because the bulb I have doesn't. When checking the fuel pump, I compressed the primer bulb and fuel came through the pump to the inline filter on the motor (which I cleaned). Is that normal for the bulb pressure to push through the fuel pump without the motor being on? Is there anything else that I should look for?