Chrysler 1970 70 hp Loss Of Power

[saintswinagain]

I have a 1970 70 HP Chrysler that starts fine and runs fine for about an hour. Then, I lose about 75% of the power. When I go WOT, the engine sometime stalls or bogs down. When I pull back on the throtle a little, the engine sometimes revs higher but not much power I thought it might be over heating? The motor just spits water. I just had new plugs, points, and a lower unit put in. Someone suggested I change the thermostat. I also had someone suggest it might be the coil. Any suggestions or help would be very much appreciated.

 

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Re: Chrysler 1970 70 hp Loss Of Power

This engine does not have a telltale. It has two exaust ports on the back of the leg, and if you have sputtering water ,(like you told it a funny joke while it had a mouthfull of seawater), it's fine.<br />As for the power issue, you mentioned the RPMs go up, but no more power. If it's like a car spinning it's tires on an icey road, it's the hub in the prop. if the RPM's remain low,and it just lugs,it could be the fuel pump,tank vent or fuel line clogged or air leak in the fuel line.<br />The fuel pump is cheap and easy to rebuild, taking a 15buk kit, and about an hour of time.<br />Seeins how the diaphram in this fuel pump is rubber, and most fuels now have alcohol in it,and the engine is 30years old, it could probably benifit from a pump rebuild.<br />I really hate those Chrysler 'air-chuck' style fuel fittings. They are hard to use at night on the water when you need to switch tanks.Mine leaked air on occasion. So I replaced mine with Merc twist on type.I haven't had a problem with them since, but not saying this has much to do with your problem....But it could.<br />Check the compression if possable. Low compression will not draw or compress fuel mixture very well, and will surface as poor performance. More importantly, the fuel pump runs from the engine's compression-- low compression=low fuel volume.<br />Good luck, and let us know what you find.

 

[saintswinagain]

Re: Chrysler 1970 70 hp Loss Of Power

Thanks for the quick reply. I looked at things a little closer last night and believe the issue is not a cooling problem (no signs of excessive heat on the heads). I pulled the "new plugs" and they looked pretty black and had a varnish odor. Cleaned em up real good and put back in. Also pulled a small peice of garbage out of the clear glass under the fuel pump. I think I'll dump my gas and make sure I'm at 50 to 1 and try running some seafoam through the motor.<br />I'll see if that works tomorrow and let you know. Again, thanks for your help.

 

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Re: Chrysler 1970 70 hp Loss Of Power

Sounds like a plan.