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Starter Bolt Solution

fastjeff

Gold Medal Contributor
Mercruiser 5.0 230 hp 1986. Starter is held by two 3/8 UNC body bolts that fit tight in the holes to align the starter.

New starter is for the later, metric engines and uses slightly larger 10 mm body bolts. This allows the metric starter to move around with the smaller 3/8 bolts.

The "solution" according to the manufacturer is to use "conversion bolts" that have 10 mm bodies that slim down to a 3/8 UNC thread. Swell, but nobody makes the damn thing (and I spent a long time looking). So...

Made up for the slop by wrapping the bolts with 5 or 6 layers of aluminum foil tape. This is great stuff with lots of uses. Starter is now solidly located and works great.

Jeff
 
Another possible solution is to take your 10mm bolt and put 3/8 threads on it with a threading die. If you use this solution keep an eye on the bolts to see If things loosen up with time and use, the foil is rather soft. Oh and a lock washer is recommended.
 
Chevrolet still offers the long bolt....pretty sure they do the same for the short bolt too....sometimes they are hard to find based on (lack of) demand...what I've seen is the 'descriptions' typically refer only to the thread size and are silent regarding the diameter of the knurled portion...
 
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