engine coupler help

yfzjim

Petty Officer 3rd Class
Joined
Jul 21, 2009
Messages
79
So I have my engine out and Im waiting on my replacement from Rapido. It has been suggested to replace my coupler while its out. I didnt realize something so simple would be so expensive. Do I really need it? Can I tell by looking at it if it is in bad shape? Next Q. The coupler I have is triangle shaped on a 14" flywheel and has a grease zirk on it but no part number. engine is a 87 200hp 305 alpha one I am replacing it with a 350 but should be no difference, it is of the same vintage. The coupler I lloked up is a 18-2175, it says it comes with the new style yoke. if I already have the new style yoke it says to use 18-2323. How do I know if I have the new style yoke? whats the difference?
 

cr2k

Captain
Joined
Mar 19, 2009
Messages
3,730
Re: engine coupler help

Look at the couplers splines. If they look good i.e. NOT pointed they are most likely good. If your old coupler and shaft were dry when you pulled it apart it would be a good idea to replace.

Looking at my NAPA (Sierra) parts book, it looks like the diff is this...
If your old engine has a one piece rear main seal you have the correct yoke.

If you have an older 2 piece seal you will need to upgrade to the new yoke.

I believe in 87 you should have the one piece seal.

Either way if your replacement engine has the same rear main as your old one you are ok.

The difference being a slight redesign of the block for the one piece main seal.

Also take your old coupler and fit it on the shaft to see of it is still snug or loose.

Most of the couplers have aluminum splines so proper lubrication (and often) is necessary. Do use a grease made for splines. (Spline grease) This is a more tenacious lube that sticks better and has ptfe qualities.
 
Last edited:

wca_tim

Lieutenant Commander
Joined
May 28, 2007
Messages
1,708
Re: engine coupler help

If the splines fit together well and the rubber on the back side (front side actually) looks good, go with it.
 

bigskiohio

Master Chief Petty Officer
Joined
May 3, 2008
Messages
882
Re: engine coupler help

i replaced mine and prices were from 85.00 to 400.00 i picked the cheapest to test as replacing it was so easy om my boat. ran it all last week and will see how it looks in a couple of months tungstenmarine.com is where i bought mine
napa,sierra ,glm mallory a bunch out there .
 

yfzjim

Petty Officer 3rd Class
Joined
Jul 21, 2009
Messages
79
Re: engine coupler help

so i should be able to get one from Napa?
 

myoldboat2

Petty Officer 1st Class
Joined
Jun 3, 2007
Messages
303
Re: engine coupler help

ouch, tungstenmarine has my coupler for 80 bucks. i just paid 128 for a sierra.
 

cr2k

Captain
Joined
Mar 19, 2009
Messages
3,730
Re: engine coupler help

Sierra Supply is NAPA. You should be able to get a NAPA Marine catalog from your local NAPA store, they may have to order it. Parts, most likely not in store but often available same day or overnite. Prices do vary a little from Sierra.

Part numbers are the same as Sierra.
 
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