Seahorse 40 won't throttle up

[oldboat1]

Get an open air spark tester (adjustable) at an auto parts store. Measure spark with both plugs removed. (should be a first step, I think).

 

[toadshade]

I just did it the old fashioned way. I have spark on both cylinders. Just can't believe it. Two new plugs and as far as I can tell, I am good to go. I have a new Sierra fuel pump on the way. Looking forward to getting back in the water. I have some glass work to do on the floor now though. Finding all those fun hidden problems with a 50 year old boat.

 

[racerone]

Is the old fashioned way done with the 2 plugs laying on the block ??------If that is your way then you are wasting your time.

 

[jimmbo]

Once the Plugs are in the engine, and the Compression raises the pressure in the cylinder, that spark might not occur. That is one of reasons a much larger gap(5/16" for old fashioned Magneto/Battery, 7/16 for Electronic) is used for testing, to verify the Ignition system is capable of providing a Spark under Operating Conditions

 

[toadshade]

OK. Good to know. But yes, I just hit the side of the engine block. I tested my good plug on both plug wires and it worked. Tested the fouled one on both and it did not. But I see your point. I know the tester you are talking about. I will make sure to give that a try.

 

[toadshade]

Well, score one more for the experienced. You were right. Spark gap tester gave me a dead wire. So I will be replacing the points and everything after all. To be honest, I was looking forward to getting in there and seeing how it all works.

 

[toadshade]

Any good recommendations on pm's that would be worth doing while I have the fuel pump and flywheel off? I am already going to get a new points/mag/condensor kit, and new fuel lines. oh and new spark wires.

 

[jimmbo]

While you have the Flywheel off, look where the upper Crankshaft Seal is. If it is Dry, great, if it showing signs of Oil, then it will need Replacing, as Oil getting out, means Air getting in, and causing the upper crankcase to be less efficient as a Transfer Pump. The seal can be replaced without taking the Engine apart. The Tool looks like a Piece of Threaded Pipe that fits over the Crankshaft with the treads going under the Seals Lip, Turning the Tool brings the threads into contact with the Seal housing and out it comes. Using a piece of threaded Pipe has been done, but if unless prepped properly, it can damage the crankshaft sealing surface, so beware

 

[oldboat1]

Any good recommendations on pm's that would be worth doing while I have the fuel pump and flywheel off? I am already going to get a new points/mag/condensor kit, and new fuel lines. oh and new spark wires.

jimmbo gives good info (above).

It's a good idea to disassemble and assemble one side of the magneto at a time to avoid confusion. With a coil in front of you (either front or rear of the engine), the points and condenser belonging to that coil will be on your right.

Wires are 7mm with a wire core. With the magneto plate removed and inverted, replace wires and coils with wires cut generously to match the length of the old one(s). One will be longer than the other. Good idea to cut the length after the coil is securely attached, with contact to inner core wire.

In your opening post, you mentioned running it on dog ears and manually increasing the throttle. You cannot tune an engine on dog ears. Additionally, you should never rev on dog ears, and certainly not by opening the throttle at the carb without advancing the magneto/timing plate. Better to run it in a barrel with water about half way up the shaft, and keep it to an idle or a high idle.

Good motors!

 

[jimmbo]

You can't properly run that engine using Ear muffs, the water pickup is behind the Prop on the front of the Exhaust Snout. I have seen people put the muffs on the Water Cover with a Screen or a few Holes that is above the AV Plate. I recommend putting that engine in a Barrel. There was an Aftermarket device by Tempo that could be Clamped tot gearcase, that allowed a hose to be attached to the Inlet on the Snout, but OMC didn't endorse that either.

Idle Speed and Carb adjustment realy need to be done on the water running in gear that way the engine is at the Height it normally be at Idle speeds and under the normal load

 

[toadshade]

I saw a bucket cut on its side after I bought the dog ears. I would have done that if I had known. It was one of those slap my head moments.

When it comes to the magneto wire length, is that based on the timing? I have not researched this yet, but is arc length an issue? Or resistance rather? Do you want to keep the wire as short as possible so it doesn't fail or heat up the magneto?

 

[racerone]

???----Sparkplug wire length has to do with where the coils are.-----Has nothing to do with the timing / arc length / resistance / or the wire heating up the magneto.-------Not sure where these ideas originate from ?

 

[toadshade]

Just a misunderstanding from looking at the kit. I just need to get it and sit down with the FSM to put it all together.

Side note, I just removed half the floorboard of my 1963 Mohawk after stepping through it. Was the plywood on these old boats mahogany?