1958 18 h.p. Seahorse issues

[Huntingducks117]

Well, I got my "new" motor running last night. I changed the lower unit lube, changed the spark plugs, cleaned the gas tank and tried to clean everything up on the the motor. I just ran it in nuetral in a trash can. It ran pretty good, but it would miss-a-beat or mis-fire every so 5 seconds or so. When I would rev it up, it seamed like it would lose power after a while when I had it opened up, and then shut off when I reduced throttle.
I figured it just needed to be ran. So I shut it off to take it to the lake. While it was sitting, I noticed that gas started leaking out of the carborator. It was like it was siphoning from the tank. When I unhooked the hose, there was a lot of pressure behind it. Is there a air release valve on those older tanks?

I also noticed that there was some cream colored grease leaking out of a hole (the hole looked like it was supposed to be there) in the lower unit.

Another question... Is there supposed to be a sponge in here? Because there is not.

Is this stuff supposed to be happening? Just wondering if I should go run it, or if I need to work on something else. What do I need to do, to get it on the lake.

Thanks

 

[wbeaton]

Re: 1958 18 h.p. Seahorse issues

The carb is either not set properly or needs to be rebuilt. Float could be stuck open or sinking. Try setting your carb. There is a procedure in the FAQ's. You can't set it while its in the barrel. Also, don't run it above fast idle in the tank.

No sponge needed. The greasy oil is normal. Its unspent fuel, oil and water emulsified. You want it to drain out.

The tank pressure is probably normal.

 

[Sea18Horse]

Re: 1958 18 h.p. Seahorse issues

Regarding the occasional misfire it's probably related to the carb problems you're having. But it would probably be prudent to check the condition of your coils. All you have to do is remove the recoil starter and the sheet metal cover on the top of the flywheel and look in the hole as you rotate the flywheel (clockwise, always clockwise. You don't want to damage the impeller vanes). Just make sure you have a nice new screwdriver of the proper size. They can be tight! Look at the bodies of the coils. If they are translucent looking epoxy they will be all cracked and split and they need to be replaced. If they are plastic bodies they have been replaced already and are probably ok.

And as WB mentions, the tank is pressurized by the second line from the motor. There is a pressure relief valve built in to the tank that limits pressure to 5psi or so. If the age and condition of the tank is questionable then getting a rebuild kit and going through the tank is a good idea. You'll also want to replace the o rings in the fuel connector where it plugs onto the motor too. Go to vintageoutboard.com or nymarine.ca or maybe even right here at iboats for the kit and orings. You'll probably find that the fuel lines in the motor itself are all hardened or getting dry rotted. You'll want to replace those as well while your doing the carb work. 5/32 marine fuel line from any OMC dealer. Good luck!

Cheers.....................Todd