Got the new 93 Seaswirl OMC Cobra 4.3 serviced and compression tested today!

[The Grayt 1]

Well took my boat to the Marine Tech just for a full check up and get some services done. We water tested it when we bought it and it ran good but just wanted a trained eye on it. We replaced the impeller on it in the oiutdrive, put new spark plugs in it which were motorcraft I think, greased two zerk fittings on the outdrive which he told me was the gimble bearing, and finally rana compression test. The numbers came back as dead even 150 psi on cylinders 1-4 and 155 psi on 5 and 6. Is that good?

Are the motorcraft plugs okay to run? They ran the plug that came out of it and said tha t the Motorcraft plug PN was SP-425 ASF52C, sound right? Also is the grease zerk fitting for the gimble bearing exposed on the omc cobra drives? Thanks

[JustJason]

1. compression is good, the deviation is well withing tolerences.
2. motorcraft plugs in a GM????? Hmmmm... you'll get varying opinions but I would ask for the manufactor specified plug... which is and Ac Delco MR43TS(or lts depending on the head)
3. Yup there is a zerk fitting for the gimbal.

[The Grayt 1]

The OMC manual said that it was okay to use Motorcraft plugs in it. I think the part number has changed though.

It says AMF32m in the original manual for the motorcraft plug. They did not have the AC delco or champion all in stock.

[cr2k]

My experience is that Motorcraft or Autolite plugs are a notch above Champions.
but you will get varying opinions on this due to others experiences. NGK also makes a damn good plug.

[The Grayt 1]

Yea, all they had a full set of was the Motorcraft for 2 bucks a pop or some NGK for 5 a piece. I went with the Motorcraft.

The Tech told me my boat was in awesome shape and had very low hours. I thought you had to remove the drive to grease the gimbal bearing... is that not true? He greased two zerk fittings on the drive.

[Don S]

I thought you had to remove the drive to grease the gimbal bearing... is that not true?

There is a grease zirk on the side of the gimbal housing with a tube that goes to the gimbal bearing. However, you really need to pull the outdrive in order to check the engine alignment and grease the splines in the coupler. That should be done at least once a year or every 100 hours, whichever comes first.
It's also the only way to check that there is no water in the bellows.

As far as spark plugs go, when it seems like it's not running right this summer, but some AC or NGK's in it and it will probably run fine.

[The Grayt 1]

There is a grease zirk on the side of the gimbal housing with a tube that goes to the gimbal bearing. However, you really need to pull the outdrive in order to check the engine alignment and grease the splines in the coupler. That should be done at least once a year or every 100 hours, whichever comes first.
It's also the only way to check that there is no water in the bellows.

As far as spark plugs go, when it seems like it's not running right this summer, but some AC or NGK's in it and it will probably run fine.

Are you implying that it will not run well on those Motorcraft plugs?

[Lodgepole]

Don't let anyone kid you. I have used autolite or motorcraft plugs for years in all kinds of engines. They beat the crap out of AC and champion.

[The Grayt 1]

That makes me feel better. When we put the new plugs in it sounded good and ran just fine to me.

[Don S]

At least someone finally posted the answer you wanted to hear.