What parts and maintenance items MUST be OEM (Mercruiser)?

[Philster]

After reading numerous threads, I would notice every once in a while somewhere it'd be mentioned that you must use part x, y or z and that it must be OEM.

I remember only a couple of these recommendations, but I don't know if there is a master list or master reference guide.

So... for Mercruiser I/O's, what parts must be OEM parts? Also, what maintenance items, add-ons, fluids, lubes are considered "musts" by the iboats' gurus?

If I am wrenching around my Mercruiser, what must be an OEM part, fluid, accessory, etc?

Alos, if it can be noted, which manufacturers are ones to absolutely avoid (I.E., say an OEM part is not required in a particular application, can we list the manufacturers to avoid? Let's say it is agreed that fuel filters can be OEM or aftermarket. Maybe "SuperCheapo" filters from "Half-Arsed Marine" are the ones to avoid. Or... Maybe the OEM part is the one to avoid).

Well, let's have at it.

 

[Bondo]

Re: What parts and maintenance items MUST be OEM (Mercruiser)?

Ayuh,... This otta be as Good as any Oil thread,....
I'll get in early,...

I think Napa filters are about the Best money can buy....
I use Sierra parts, usually without regret(although Don talked me into buying a Merc. shift cable)...
GLM Manifolds are a Roll of the Dice,... You usually Loose...
I run Mobil 1 Syn-oils in my barges, without regrets...
Hoses, fuel, igntion,+ electrical parts should Always be Marine grade stuff....

 

[frank246]

Re: What parts and maintenance items MUST be OEM (Mercruiser)?

I got two,
The waterpump house r/mr/alpha one gen 1 (with the cup in it) and impeller.

1/The gasket surface of some aftermarket pump houses are not complete flat, thus not compressing and sealing the aereas in between the fw nut and the two nuts on the side of the pump house making the pump leak water and not 100% efficient.
Now..this leak is not noticeable (unless you have wet through hull exhaust) as the leaking water from the pump leaves together with the rest of the cooling water through the prop.
2/Looks like Oem impellers (vanes) are made out of better material than aftermarket.
Also some aftermarket impellers fit way to snug on the key and need some slight mod. to fit properly.

 

[achris]

Re: What parts and maintenance items MUST be OEM (Mercruiser)?

Almost all the parts can be aftermarket if you want. As long as those that need to be J1171 (Marine) rated, are. Mostly that's anything electrical or fuel.

I have used OEM and aftermarket, and generally use OEM where I can. The thing I consider is the warranty. OEM parts are warranted for 12 months, AND the warranty extends to consequential damage, most aftermarket stuff does not. For me, that's particularly important for things like impellers and exhaust elbows and manifolds where a failure of a non-genuine parts will cause other problems, which includes destroying an engine..

One item I found a big difference in was a uni-joint bellows. I used a GLM once... The rubber was a lot stiffer and harder to get on the bell housing and gimbal housing. I only use OEM bellows now.

A brand to steer clear of, and I think most here will agree, is Champion spark plugs.

0.02

Chris......

 

[fat fanny]

Re: What parts and maintenance items MUST be OEM (Mercruiser)?

I'll chime in early as well. I have contributed to threads when the questioned was asked what is the best for X & Y and just gave my opinion on my experiences only and some on what I have heard from reputable sources from this forum. But I will only chime in now when it comes to things such as ignition parts and the common sense parts such as fuel pumps and the afore mentioned ignition parts. Oils are oils and grease is grease so the choices are yours but when it come to cables, bearings and outdrive parts it's OEM.

 

[FreeBeeTony]

Re: What parts and maintenance items MUST be OEM (Mercruiser)?

One item I found a big difference in was a uni-joint bellows. I used a GLM once... The rubber was a lot stiffer and harder to get on the bell housing and gimbal housing. I only use OEM bellows now.

.....

This is one item I didn't want to chance with an aftermarket part.......