25 HP Sea King

[sekory]

Hi there,

I just purchased a rough running 25 hp Sea King and was wondering a few things. I was told some water had gotten into the line hence it rough running (doesn't idle just quits with a sputter) and that new gas should clear it up, anything else I might want to be aware of in getting things running smoothly again? It's model number is GG8985A - how would I go about finding what year this is and finding a service manual? I hope to get it running dependably within the next couple of weeks to take advantage of late October salmon fishing here in Portland, Or. Any and all help is welcome. Thanks!

Robert

 

[CATransplant]

Re: 25 HP Sea King

That's a 1958 Sea King you have there. It's very similar to the RD series of Big Twin outboards made by OMC. It was made by their Gale division, and is very similar to the mid 1950s Johnson and Evinrude 25 hp models.

Most common service parts, like ignition parts and carburetor parts, are available, either from your Evinrude dealer, or as aftermarket parts by Sierra Marine (available at NAPA auto parts outlets) or right here on iboats.com.

The fuelil ratio for that outboard is 24:1, and don't listen to anyone who says it's OK to use 50:1 in it.

Plugs are Champion J4C, or J6C if you're running a lot at low speeds. Gap for the plugs is .030". Points gap is .020". Unless the magneto coils have been replaced at some point, yours are probably cracked and damaged. Your flywheel probably has an oblong port, with a cover screwed on, that will let you inspect and adjust points and see the coils. To access that, the recoil starter must be removed.

Your outboard has the potential to be a very reliable powerplant for your boat.

 

[sekory]

Re: 25 HP Sea King

Thanks for the info! I'll look more closely at it when I get home and hopefully get it running well before long. I assume an Evinrude service manual would work for this model?

 

[CATransplant]

Re: 25 HP Sea King

Yeah, pretty much. But not the 1958 one. Yours is more like the 1955 25 hp, except that I believe it has a fuel pump...not installed on the johnnyrudes until 1958-59.

The techniques in the manual are the same, however, for the mid 50s 25 hp outboards.

Trouble is, the only factory service manual that's available covers all 1 and 2 cylinder outboards from 1941-1964, and it costs almost $100.

Frankly, about all you'll want to do to that outboard is a carburetor cleaning and kitting, ignition work, and an impeller replacement. Anything more than that is going to run way too much money to be worthwhile. So...the SELOC manual that covers the 1950s models will probably do. Not many changes happened until 1958, when many changes occurred. Again, yours is based on the older models.

Fortunately, for that type of work, the parts are the same for yours and the mid 1950s johnsons and evinrudes. It uses the "universal magneto" for ignition, and the carb kit fits a range of models anyhow. The impeller is also the same in all of those mid 1950s big twins.

For about $200-250, you can replace the entire ignition system, rebuild the carburetor, and replace the water pump impeller. With that done, assuming the engine has equal good compression on both cylinders, you're pretty much done. Check compression before buying any parts.

Couple of things, though: the lower unit or gearbox might possibly have a bad clutch dog, which would cause it to jump out of gear. If you can get it going OK, give the outboard a good run on the water before spending a bunch of money on other parts. You can replace the lower unit or clutch dog, but...

Also, when you drain the lower unit oil to check for water intrusion, do not remove the screw with the phillips head that's near the drain plugs. It is the pivot pin for the shifter, and is a pain to realign if you remove it.

There's tons of help here for the Big Twins, so ask freely. You can actually ask your questions in the Johnson/Evinrude section. Just identify your outboard as a Gale, and folks will be glad to help.

 

[steelespike]

Re: 25 HP Sea King

A great motor; had the 1960 version.
CAT's got it well covered I would just add to start with a compression test.
100 psi per cylinder would be excellent but it will run on less.Even pressure cylinder to cylinder is important.Sometimes a decarb will help improve compression.