1974 135 Johnson plug and tilt questions

[The Grail]

'Morning,

Any help with these two items would be appreciated.

Plugs:

My 1974 135 Johnson had NGK B8HS-10 plugs installed when I bought it, and three new ones in the dash. I bought one new one and installed all four, gapped at .030. It didn't seem to run any differently. I have to go at no-wake for about 20 minutes out and 20 minutes back in, and the plugs have gas on them when I take them out. This motor calls for Champion UL77V, surface gap plugs. I've read in forums that they're not great plugs. Are they the best for this motor? I don't think I have any problems, I'm just getting used to this motor, and want it to run it's best.

Tilt/trim:

My tilt/trim does not work. Is the tilt/trim motor and pump normally mounted inside the boat? This one is on the outside, beside the transom mount. The pump motor sits halfway in the water, and would seem to explain why it doesn't work. I took apart the electric motor, and it's really rusted inside. One piston is locked up at one point, but I think the pump still works (with the electric motor removed, I spun the pump with a drill and it worked somewhat.) When I rebuild or replace it, should I mount it inside the boat?


Thanks, and have a great Memorial Day Weekend!

 

[RRitt]

Re: 1974 135 Johnson plug and tilt questions

if you mount pump inside boat then oil tubing might be a problem. If you decide to do so then use kunifer tubing instead of SS. It is slightly more expensive but it will be less destructive towards your aluminum in saltwater. As a bonus it will be easier to bend and shape.

theoretically, your pump and motor are sealed units and could operate just fine underwater. Realistically they are made with multiple metals which will wage war against each other in saltwater. Aluminum is weakest and always suffers the worst damage. Unfortunately the aluminum parts are also the most expensive to replace. Ideally the pump would be located in a place where it might get splashed but is easily washed down. I am assumming that when you say it is halfway submerged that you are exaggerating. your description almost makes it sound like pump is bolted to transom. It should be mounted to bracket on engine.

it is hard to say much about the innards of your motor/pump beacause there were two different makes used. one make (calco) still has parts from brp but they are expensive. the other make (prestolite) is NLA but had heavy engineering emphasis on using industry standard parts (so most stuff is off-the-shelf industrial supply). Either way - if inside of motor is rusted then the field frame needs to be either replaced or stripped.

the hydraulic tubes are relatively easy rebuild once you get them apart.

 

[Joe Reeves]

Re: 1974 135 Johnson plug and tilt questions

Use the alternative OMC recommended Champion spark plugs QL77JC4 and set the gap to .040 .

 

[The Grail]

Re: 1974 135 Johnson plug and tilt questions

Thanks, Joe, I'll pick up a set of those plugs.

RRitt, the t/t pump and motor are mounted to the transom mount, (the part that attaches the motor to the transom) not the transom, but it does set in the water. The pump is submerged, and about 1/3 of the electric motor is uderwater at all times. The joint where the pump and motor meet (it's a Prestolite) doesn't have a gasket of any sort, so I wanted to avoid this problem when I re-build or replace. Thanks for the info - I'll look into the kunifer tubing.

 

[RRitt]

Re: 1974 135 Johnson plug and tilt questions

the pump/resevoir has an oring seal that is historically one of the most durable seals in the system. generally speaking the seals that break first are the flat gaskets between field frame and resevoir, the cap bolt sealing washers, and the internal seal between resevoir and armature. If it was me then I would probably just get a piece of 3/8" aluminum plate from hardware store and drill holes into it that raise pump straight up a few inches. You could even tap threads into the bottom holes for a flush fit. A bench grinder or belt sander should knock the corners off and make it less dangerous. Then I would use brass coupling to add a few inches of tube extensions onto existing oil lines.

 

[RRitt]

Re: 1974 135 Johnson plug and tilt questions

also - you may want to make sure that the back end of your boat is suppossed to set that low in the water.

 

[The Grail]

Re: 1974 135 Johnson plug and tilt questions

I thought of that too, but the boat seems to be setting in the water correctly. It's at the bottom paint line (I guess that could be incorrect, though), and the water is just below the two drains at the transom.

I'm currently keeping the boat in the water at a friend's house, so I plan on putting it on the trailer soon so that I can remove the pump. I'll look into making a bracket to raise the t/t pump, or put it inside the boat when I re-install it.

Thanks.