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    67 thunderbolt 500 spark question

    I have a 1967 thunderbolt 500. It starts first turn of the key and idles fine in neutral. Under load it does not perform well.....10-15 miles per hour at wot on a 15 ft Grew. At lower speeds at the marina it also stalls. When I remove the plugs (brand new) I don't see much evidence of use on...
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    500 thunderbolt low rpms under load.

    PLEASE HELP. I bought this boat last fall with a thunderbolt (67) 500. When I started it this year it was hard to start and had no power. I took it to a private marine mechanic who rebuilt both carbs, fuel pump, replaced plugs, and cleaned the fuel filter. It starts easily now and idles great...
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    performance problem with 500 thunderbolt

    I have a 1967 mercury 500 thunderbolt that I recently bought on a 15 ft grew fiberglass boat. It starts on the first try and idles fine, the problem is on the water I can only get about 7 or 8 miles per hour out of it. Seems like it goes to about 1/4 throttle and stops......i can throttle it all...
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    how does a choke solenoid work

    I have a late 60"s thunderbolt 500 with electric start. The choke operates by pushing in the key which closes the choke. Should it stay closed once I release the key? Mine doesn't, and the engine won't run properly with the choke closed. I have to remove the engine cover and push down on the...
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    test for spark on 67 Merc Thunderbolt 500

    I tried to start my motor today for the first time (I just bought the boat used a few months back). There doesn't seem to be any spark, and the only way I knew to check for this was remove a plug and crank the engine with the plug touching the engine frame. The battery is brand new, and the...
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    Mercury 500 thunderbolt gear problem

    I recently bought this motor and tried to start it today for the first time. I have it in neutral and the prop spins freely, but when I try to turn over the engine it is extremely difficult to turn over and the drive shaft is turning the prop. Is this normal? If the engine is in neutral...
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    Installing a Quicksilver control to a Mercury 500 Thunderbolt

    I need to install a quicksilver control on my 67 thunderbolt which had only 7 wires, and the quicksilver has 11 wires. I can eliminate 3 wires (blue/white, green/white, and purple white) which operate the trim which I do not have. I can also eliminate the tan/blue on the new control which is a...
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    Mercury 500 Thunderbolt question

    I just purchased an older boat with a Merc 500 (late 60's). When I bought it the guy said the impellar is new but the prop made a clicking sound when you spin the prop by hand. The prop only turns clockwise by hand, should it spin freely in both directions. Also, the motor had no controls on it...
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