'68 650 Merc Question

[robpoe]

I have a 650 Merc that's been .. neglected .. for probably the last 8 years. I recently asked the PO (a friend of mine) when he last had it serviced / tuned / whatever. He said "I dont think I ever had anything done to it". I asked about the impeller .. to which he said "the what?"<br /><br />I used it last season about 6-9 times. It peed (a little at idle, nice stream at WOT). Coupla problems.<br /><br />1. It doesn't idle worth a ****. You put it in gear, you either gotta give it gas, or use the advance lever to keep it running out of gear.<br /><br />2. The hole shot is HORRIBLE. You WOT it from a standing start and the thing goes WAAAAHHHHHH (sounds like it's bogging down bad). Put it in a tight turn and it bogs hard, too. <br /><br />It leaks. You know it's my boat, by the oil slick behind it when it's stopped. The gear oil isn't milky .. it looks fine. I think it's gas / oil mix, but I dont know if it's leaking before combustion or if oil's coming out the exhaust.<br /><br />SO ... what do you all recommend? <br /><br />1. Carbs (probably need done)<br />2. Plugs?<br /><br />Does this motor have points?<br /><br />Or compression test first?<br /><br />Does this motor need to be de-carbonized? Reed valves? I saw the price on distributor cap/rotor/etc and about pooped myself. But I do like the look of that old girl and would like to keep it.<br /><br />At WOT it runs pretty good. It's on the back of a Bayliner Capri (16' open bow runabout) and goes about 31mph (by the GPS). The prop got dinged up pretty good when I hit a rock, but it was "even damage" (in other words, same indentation on both sides, I filed it out and it works just as it did before).<br /><br />Thanks in advance.

 

[joblo33]

Re: '68 650 Merc Question

I'd recommend everything you suggested in this order:<br />1-Do a compression test first to make sure it's worth tuning up.<br />2-Report back <br />3-Then clean/rebuild the carbs, judging by the previous owner and your idle issues they'll need it.<br />4-Check for spark.<br />5-Report Back <br />6-Decarb it. (can't hurt)<br />7-Change plugs after the decarb has run through.<br />8-Change that impellor before you have to deal with a broken impellor blade in the water jacket! (you could make this #2)<br />9-Test run!<br />10-Report back <br />Good luck,<br />Eric

 

[timmathis]

Re: '68 650 Merc Question

I found a 1500 150 H.P. with the same history. They never done anything to it. You would be surprised if you only knew how many old mercs out there that are still running that have been neglected!!! That alone tells me that are built to last and are tuff.<br />It was hard to start also ran a little ruff and did not like to idle. Just like yours.<br />It has been running like a bat out of hell now for 3 years.<br />All that I have done to it is.<br /><br />Replaced any old brittle wires.<br />New plastic fuel tank.<br />New carbon brush and spring in distributor cap.<br />New plugs.<br />A decarb With Deep-Creep and seafoam.<br />Timing And sync. (Per Clams post)<br />Changed lower unit oil.<br />Adjusted carb's. (Falls under Linc & Sync)<br /><br />That is all I have done to it so far. It runs like a scalded cat and purrs like a kitten.<br />I was lucky and did not have to do a carb<br />job (due to a good fuel system cleaning with seafoam 2 gal fuel to 1 quart of seafoam) it smoked a little but helped with the decarb.<br />I plan to change the impeller soon even though it still pees like a colorado pack mule.<br /><br />I would recommend you do the impeller, check fuel lines do a carb job and anything else you see fit. <br />Better safe than sorry. <br />Good Luck, Tim <br /><br />P.S. I would check with Clams, Laddies or one of the inline pro's and see if they recommend anything else....

 

[PuckHog]

Re: '68 650 Merc Question

I have a '69 650 and was dismayed to discover the distributor cap has been discontinued (currently no aftermarket support), and the rotors are indeed eye-poppingly expensive. As much enjoyment I've gotten from my 650 made it worth it, though.

 

[timmathis]

Re: '68 650 Merc Question

You can get a used cap and rotor or plug wires from many suppliers. From time to time ebay will have whatever you may need. Tim

 

[Clams Canino]

Re: '68 650 Merc Question

Unless the cap is broken. clean it, run it through tthe dishwasher and replace the little carbon brush. Walla! New cap.<br /><br />-W

 

[robpoe]

Re: '68 650 Merc Question

Clams - where can I get the little carbon brush?<br /><br />I'll definately need to replace some of the wires. The ones under the cowling look kind of like the ones that were in the control box....Just a little MORE insulation (i.e. it hasn't chipped all off yet, just almost). <br /><br />I wanna pull the motor for all this work (heated garage not big enough for the boat, too!) but I also know how much of a bi*** it was to pick up and mount .. Guess I'll have to bite the bullet, eh?<br /><br />Maybe this time I'll figure out how to construct a motor mount that doesn't require that the motor be about 50 feet off of the ground (and at an angle thats impossible to work at .. tee hee). Also think I might end up putting it on casters...<br /><br />Dunno..

 

[robpoe]

Re: '68 650 Merc Question

But thanks everyone for their input so far! I'll report back as soon as I have something to report!<br /><br />-- rob

 

[Clams Canino]

Re: '68 650 Merc Question

The little carbon brush is a dealer item. <br /><br />If you post or email me a pic of the motor plug off the harness, I can tell you if a cheap replacement is available.<br /><br />-W

 

[PuckHog]

Re: '68 650 Merc Question

Outboardparts.com has aftermarket internal wire harnesses at a reasonable price. Switched out the harness on my '69 650 and it made all the difference. I also cleaned up my distributor cap as per Clam's advice about a year ago and have had nothing but happy boating.