Help on Formula Thunderbird drive

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charlie1976thunderbird

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I have a 1976 21 foot formula thunderbird with a 302 and a mercruiser 370 stern drive. It sat for several years and now will not turn over. Engeine turns about 5-10 degrees when ignition turn, but will go no further. Prop also turns small amount when engine turned, even in neutral. In neatral prop will not free spin. Drive train seems to be locked together and jammed. How do I trouble shoot to track down area to focus on.
 
alldodge

alldodge

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Re: Help on Formula Thunderbird drive

Pull the drive off and see if it will turn over, but if it starts turn it back off...... no water. If it won;t turn over then time to pull the engine maybe. Just comments from brief discription.
 
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charlie1976thunderbird

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Re: Help on Formula Thunderbird drive

My terminology will be off, but will get better with this project. I have a manual coming to guide me. To remove drive, I take of the "lift" mechanism on each side and remove 6 bolts and slide it back, correct? Any idea how much the drive ways? 2 able body guys able to handle it? I will amke a cradle to hang it on tomorrow. Thanks for awefully quick response.
 
alldodge

alldodge

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Re: Help on Formula Thunderbird drive

Yes, remove the hydraulic cylinders on each side, remove the 6 nuts and side it out. Note there is also a water pick up which needs to be removed prior but tilting the drive up or remove partialy. The tab is turned about 45 degrees and then pulled out. The alpha should be no problem with a couple guys, weights about 100.
 
NHGuy

NHGuy

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Re: Help on Formula Thunderbird drive

They don't weight 100# but their bulk makes them seem like it. When you get it off try to very briefly crank or run the motor, it won't have cooling water. If it cranks great, if the motor cranks the drive may be stuck. That would keep the motor from spinning.
 
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bonzoscott

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Re: Help on Formula Thunderbird drive

Before going further, read much more on this forum and you may want to purchase and alignment bar - among other items.
 
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charlie1976thunderbird

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Re: Help on Formula Thunderbird drive

I removed the stern drive (6 nuts) and removed. The U joint inside and the prop spin freely. Thus the problem is forward of this. Is there a way to sepately check engine and gear box/transmission without separating them? Tomorrow or Wednesday I will get my Seloc book and will then have a much better grasp of the process and terms I will need to talk to all of you. Thanks for all the help thus far. Oh yeah, The spiders have been really busy under the stern drive.
 
mercs4mark

mercs4mark

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Re: Help on Formula Thunderbird drive

When your seloc Manuel comes, take it from the mail box and walk directly to the trash can and deposit it there, under no circumstance open a page and start reading
 
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haulnazz15

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Re: Help on Formula Thunderbird drive

mercs4mark said:
When your seloc Manuel comes, take it from the mail box and walk directly to the trash can and deposit it there, under no circumstance open a page and start reading
Click to expand...

Don't be so dramatic. It's not that bad, it's just not as good as having a Mercruiser shop manual. In any case, I'd pull the spark plugs on the engine and try to turn it over (either with starter or by hand) to make sure there isn't water in a cylinder.
 
Bondo

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Re: Help on Formula Thunderbird drive

charlie1976thunderbird said:
I removed the stern drive (6 nuts) and removed. The U joint inside and the prop spin freely. Thus the problem is forward of this. Is there a way to sepately check engine and gear box/transmission without separating them? Tomorrow or Wednesday I will get my Seloc book and will then have a much better grasp of the process and terms I will need to talk to all of you. Thanks for all the help thus far. Oh yeah, The spiders have been really busy under the stern drive.
Click to expand...

Ayuh,.... Welcome Aboard,... Ya just did, the Outdrive,... Next thing forward is the motor,...
 
achris

achris

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Re: Help on Formula Thunderbird drive

mercs4mark said:
When your seloc Manuel comes, take it from the mail box and walk directly to the trash can and deposit it there, under no circumstance open a page and start reading
Click to expand...

haulnazz15 said:
Don't be so dramatic. It's not that bad,.....
Click to expand...

I think he hasn't been dramatic enough. Those selocs are dangerous. Worse than missing information is inaccurate information, and that thing is full of it....

OP. If you want a proper manual -> Factory shop manual
 
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muc

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Re: Help on Formula Thunderbird drive

If the OP has a 370 drive. That would be a TRS and it will have a transmission bolted to the back of the engine. To separate the two the engine will need to come out of boat.
 
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cruzn

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Re: Help on Formula Thunderbird drive

muc said:
If the OP has a 370 drive. That would be a TRS and it will have a transmission bolted to the back of the engine. To separate the two the engine will need to come out of boat.
Click to expand...

He said in the original post it's a 302. Did Merc ever put that small an engine in front of a TRS?
 
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haulnazz15

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Re: Help on Formula Thunderbird drive

I believe they had a 225TR or 225TRS designation at one point. Haven't seen it designated as a 370.
 
Bondo

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Re: Help on Formula Thunderbird drive

Ayuh,... Hard to believe it's a TRS on a tiny 21' hull,...
 
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charlie1976thunderbird

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Re: Help on Formula Thunderbird drive

Bond-o said:
Ayuh,... Hard to believe it's a TRS on a tiny 21' hull,...
Click to expand...

The back of the stern drive that I removed has 370 on it, and it weighed a lot. I will take some pictures of the stern drive, boat, and engine compartment. Can I upload photos on this thread or only text?
 
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