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  1. V

    Tachometer question?

    5.7l with thunderbolt5, should the gray wire at the tach be constant power with the key on, engine off? It has constant power and pulse with engine running? Seems like it should not have any constant power, only pulse? Am i correct in my line of thinking? Trying to diagnose the tach not working...
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    T-Stat check balls 5.7l

    What purpose do the check balls in the hoses to the risers serve?
  3. V

    Ignition question

    I am repowering a 1987 4.3l with thunderbolt ignition, to a 97 5.7l with thunderbolt, does anyone know how i could go about wiring the ignition on the 5.7, using the 4.3 wiring harness?
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    Carb question

    Does anyone know what cfm a 4bbl quadrajet is on an 87 4.3l 205hp engine is?
  5. V

    another gen 2 question?

    What is the cable? / wire going into the lower unit? The one right by the shifter connection between the 2 halves of the drive?
  6. V

    gen 2 ?

    I dont have the serial #'s but i have a general question, can a gen 2 drive be replaced with a alpha one without changing the gimbal housing or the gimbal ring?
  7. V

    gear ratio question ?

    How will a 1.84 alpha one, affect a 130 hp merc? What is the correct ratio for this engine? 2.00?
  8. V

    Need a gimbal brg, but dont know which #

    I need a gimbal bearing, for a 1980 cobalt, merc 260. 5.7l v8 pre alpha drive. I cant read the ser # on the bell housing. And im not finding a part listing for the 260.. Anyways, Heres the problem, The transom plate broke on both sides of the engine, it broke the ears off that the rear motor...
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    Motor mount box replacement question.

    Ok, so the lag screws pulled up outta the motor mount boxes due to an accident on the highway. I pulled the engine today and thought all I was going to have to do was drill the existing holes and epoxy dowels in them to hold new lag screws. Well, once the engine was out and upon further...
  10. V

    Motor mount lag bolts pulled out!!! PICS ADDED

    Had a slight mishap and the front motor mount bolts pulled up outta the stringers.. It didnt hurt the stringers at all just pulled the bolts out.. How would I go about repairing the bolt holes to hold bolts again?
  11. V

    will this part work on a mc-1?

    http://www.marinepartsexpress.com/Merc_Schematics/R-MR-ALPHA%20ONE%20STERNDRIVE%201983-1990/6225577_0D469858/TRANSOM%20PLATE-SHIFT%20CABLE.pdf will part 1 fit a pre alpha 260 5.7l v8 Thanks in advance..
  12. V

    Can u help identify a part?

    What is the part called that holds the back of the engine to the transom plate on a 1980mercruiser 260 5.7l v8? If you refer to the thread in the trailers and towing forum and look for the post titled "the cobalt is a total loss" you will read what happened. this piece is broken on both sides of...
  13. V

    The Cobalt is a total loss.

    We had a great day yesterday, went to Indian lake and watched the fireworks on the boat, the kids and everyone had a great time until we were on our way home, We made it about 15 miles into our 60 mile ride home, When outta nowhere, the biggest deer I have ever seen was standing right in front...
  14. V

    outdrive wont go down. think I fixed it....

    1980 MC-1 drive.260v8. trim goes up just fine. Wont go down, when it does go down it is very slow. Most the time it wont go down at all unless I push on it and help it down. Took the pump out of the boat and bench tested it and i get what looks like good fluid flow from both ports. I also...
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    MC-1 trim question

    1980 cobalt 260 MC-1 drive. Last weekend drive would trim up ok. But would not go down. The pump motor was running, didnt sound strained or anything. It would trim down when I throttled the engine up. When I got the boat home I checked everything visually and everything looked ok. I checked the...
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    upper unit seal replacement ????????

    Does anyone know if you can replace the seal that is in the upper drive unit on a model 1 mercruiser? It is the seal that is in the bottom, where the lower unit driveshaft splines are. I really dont wanna have to take the upper unit apart if i dont have to. Thanks, Steve
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    Mallory Unilite question ?????

    I have a 1980 Merc 5.7l 260hp v-8. It has been converted from points to a Mallory Unilte. My problem is, at cruising speed of 3000 rpms i get a studder and rpm loss, then it clears up. Sometimes it will do it at wot and other rpm ranges. sometimes it will give a little pop through the carb...
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    How much water flow?

    How much water should the impeller pump? I took the water inlet off at the thermostat housing and started the motor on muffs. at idle the water barely over flows out of the hose. (the hose is pointing straight up ) at 2500 rpms the water shoots up about an inch and a half. it just doesnt seem to...
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    oil in lower unit,I have a leak HELP!!!

    Ok, so in another post I am working on a cooling issue, now that ive put the lower drive back on, the drive oil is leaking into the lower case. In the area of the splined shift shaft. And is leaking out of the drain hole in the lower unit and the hub around the prop. The top of the input shaft...
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    5.7 prealpha running hot (pics posted) UPDATE!!!!

    Hello, I have a 1980 Cobalt 19cd, 5.7l, 260hp, Pre alpha. As far as i could tell the drive serial# is, 3343145 The engine serial# is, 5571786 Heres the problem, I installed new center riser manifolds, new risers, new thermostat housing and thermostat. (140f) And thru hull exhaust. When...
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