Extra parts got my 1974 135hp back on the water

[WinnerCougar74]

I just wanted to share some recent issues from a fishing trip. 2 times the engine died and would not start out on the water. Fortunately I have a 9.9 kicker motor and it got us home. The kicker cost me about $800 total so that was cheap insurance. Well worth it for peace of mind with a 47 year old motor.
First time: some how the #3 plug electrode got smashed. They were "gapped" NGK 4322 (BR8HS). Checked compression and inspected #3 cylinder and it all looked good. Best guess is the spark plug electrode heated up and caused detonation which fortunately only smashed the plug electrode. Installed NGK BUHX "gapless" plugs. The previous owner had I had BUHW. The BUHW foul easily. The BUHW have a wider gap and do not have an anti-foul design. The BUHX have anti-foul design and smaller gap and are the factory recommended plug so I'm going to try sticking with these. So far I have been able to do a lot of trolling without them fouling. So I'm sticking with NGK BUHX for now.
Second time: tear in fuel pump diaphragm caused fuel to dump into the exhaust and out the bottom carb. Started out thinking is was the float bowl seat but I was wrong. It was the fuel pump diaphragm. Replaced it and it ran good. Some on this sight said a backfire or cough could cause this. Coughing is common on my motor so the fuel pump diaphragm is likely to be a week point for this engine. Fortunately I bought many diaphragms so I put a new one on and was back on the water.
Third time: points were corroded and engine would not run well enough to get up back to the dock. After much time trouble shooting I found the very corroded points. I had just replaced them in April. Amazed they would have failed so soon. I put new ones in and was back on the water. I have heard if you are using and non-CDI ignition you do not need a condenser but I'm thinking of trying a condenser to make the points last longer.

After I made all of these repairs the motor ran good for 3 days.

Lessons learned. Have extra parts like, fuel pump diaphragms, primer bulb, fuel line and fuel line wire ties, spark plugs, points, seals and gaskets with you at all times because it seems like you will need them. Keep almost any parts you replace in a box in the truck. They just might get you back on the water during your vacation. The extra parts might even get you back on the water. This one is a no brainer but also keep tools on the boat including a good flat head screw driver, plyers a set of SAE wrenches and sockets and a spark plug socket.

Please post your general suggestions for keeping these Chrysler motors going either on the water or at the dock.

 

[alldodge]

I have heard if you are using and non-CDI ignition you do not need a condenser but I'm thinking of trying a condenser to make the points last longer.

Just getting into the Chy OB but condenser's have always helped points to last in everything else, wonder why they say no in this motor?

 

[WinnerCougar74]

The points aren't cheap depending on where you get them and they are tough to replace/adjust because the distributor is upside down so I'm gonna experiment with adding a condenser and I will post the results.

 

[Nordin]

If you have convert to auto style ignition as I think you have, there must be a condenser connected.
The condenser has two functions.
1. Keep the points clean from arcing that will destroy the points.
2. It boost the spark at the plugs.
If you have auto style ignition you should use regular plugs with a bent electrode and my experience is that an auto style ignition system has problem to spark the surface gap plugs cause they need a higher voltage to spark .

 

[WinnerCougar74]

This is exactly what I have read before. The condenser helps with corrosion on the points when running an auto style setup without a CDI box. I was running the Magnapower and the points only lasted a sort time before they pitted badly. Weird.

 

[Nordin]

From my experience and what I have read it is very important that the points is clean when you run with the Magna Power I battery ignition system.
With the battery Magna Power I system or any other kind of CD ignition such as MDS or other brands, the points is the trigger for the CD box (it is also a kind of trigger in a regular auto style ignition system) but the amount of current flowing through the points is much lower then in the auto style system and a bit of current through it is also good to keep the points clean.
So a amount of current through the points is good but not to much, cause if it is to high arcing will destroy the surface of the points.
Then the value (Farad) of the condenser is also important so it matches the ignition coil value (Kohm). The right value of the condenser minimizes the arc at the points.