OMC stringer shifting problem

[jmeydenbauer]

I just picked up a 1977 Thunderbird Formula that has some problems. It's got a ford motor and I was told it's a 351. It's got a 4 bbl. Holly double pumper on it. I read that there should be an identification tag on the valve covers but there isn't. From what I've read, the only 1977 model with a 351 was the OMC 235 hp unit.<br /><br />I'm new to stern drives but from my reseach on this site, it appears to be an OMC stringer 800 with electric shift. Drive is painted white and has the large rubber boot. Seperate tilt and trim. Previous owner told me he never messed with the trim, he only used the tilt while underway ... ouch. A no-no from what I've read about these drives. Ball gears appear to only be worn @ 25%<br /><br />The sterndrive has an electronic shifter and the drive will shift into forward and reverse when the engine isn't running. I checked by trying to turn the prop with the motor off. But it isn't shifting when the motor is running. The lever moves easily but no clunk or anything and the prop doesn't move. <br /><br />I read that these need to be shifted at a very low rpm which it was when I shifted. Almost to the point of stumbling.<br /><br />I've got a manual on order but it won't be here for another week or so. One note, the previous owner said the drive made a very loud grinding noise last time he had it out and he needed to get towed in. I expect to find stripped gears somewhere in there.<br /><br />I may try to pull the sparkplugs and see if turning the engine over by hand will turn the prop when it's in gear. Draining the oil should give me some more insite as to it's condition.<br /><br />Any other ideas short of pulling the drive?<br /><br />Also any other places to look for the motor identification. I found the OMC tag on the sterndrive.

 

[Boomyal]

Re: OMC stringer shifting problem

Chances are, if you have a holley double pumper, it's a 351 Windsor. If it has the stock cast iron intake manifold, the firing order will tell the story. I forget whether it's stamped forward of the carb or to the rear but a 351 will be marked 13726548. If the firing order has been ground off you have a 190 hp 302. If the firing order is 15426378 you have a 175 hp 302. <br /><br />As to your outdrive not shifting into gear(forward and reverse?) you may have a switch problem in the throttle/gear lever. If it shifts into one but not the other you have a broken slinky in the lower unit. There could be other causes but these are the most likely. Forget pulling the sparkplugs.<br /><br />If you have to spend much money to fix that outdrive I'd try to find a 1978 or later model 800 cable shift outdrive. It will bolt right up to the intermediate housing but you will need new shifter, cable and doo dad that they mount on the inside of the transom. I had it done to mine back in '78 when the electric shift kept breaking.