Need help with engine coupler

[MN86_4winns]

History: I just pulled a 1986 GM 305 (230hp) that has a cracked block (18 year old kids know nothing about winterizing). The 1986 305 block is the new style w/14" flywheel. I just received a 1987-1996 GM 350 from RapidOMarine and the 305 flywheel fits.

When dismantling the 305 I noticed excessive play between the coupler and u-joint shaft on the Alpha one. It appears that the coupler is worn. I can't find any numbers on the coupler. The coupler is triangular with the holes 11" apart. It looks like couplers 18643A5 or 18643A7 without the snout.

Will my u-joint shaft (9.5" long) work with a 18643A5 or 18643A7 coupler? Or do I need get a new shaft with the coupler?

 

[Don S]

Re: Need help with engine coupler

DO NOT use a 12" flywheel on that engine, Even if you think "It Fits", it doesn't .
Get the proper flywheel for that engine, or you will have balance problems (if you ever get it started) because you also won't find a starter to fit that block and the smaller flywheel

 

[MN86_4winns]

Re: Need help with engine coupler

??? The flywheel isn't 12" it's 14".

 

[MN86_4winns]

Re: Need help with engine coupler

What is the difference in the mercruiser couplers 18643A5 and 18643A7? They both appear to mount to a 14" flywheel.

 

[Don S]

Re: Need help with engine coupler

The A7 is the older style coupler used on engines with SN 0F000000 and below, while the A5 is used on the newer SN 0F000001 and above. The newer coupler (A5) has a longer tube with grease zirks on it to lube the shaft. The older one did not have that extra tube.
The newer one requires a yoke shaft with 3 orings on it. The third oring is to hold the grease in better and dirt out.

 

[paininthe_butt]

Re: Need help with engine coupler

The A7 is the older style coupler used on engines with SN 0F000000 and below, while the A5 is used on the newer SN 0F000001 and above. The newer coupler (A5) has a longer tube with grease zirks on it to lube the shaft. The older one did not have that extra tube.
The newer one requires a yoke shaft with 3 orings on it. The third oring is to hold the grease in better and dirt out.

so is it safe to say the on my 1990 starcraft 191s with numbers (drive serial numbers OD324097, engine serial D442738, and OD482131 on the gimbal housing) that i can technically use either one. i keep it clean and in fresh water.

 

[Don S]

Re: Need help with engine coupler

Welcome to iboat pain, you really need to learn to start a new thread with your questions not dig up old threads to hijack.