1979 Evinrude 75 hsp problem

My husband and I are amateur boat owners (first boat) and need some help. When we first got the boat, it hadn't been maintained well but ran. It rain great the first couple of times on the lake but the last couple of times it runs fine for a few minutes and then starts "blubbering" and loses power. My husband thinks it might be the coils but they are pretty pricey. Is there something else we can consider before that investment? Thank you.

Re: 1979 Evinrude 75 hsp problem

it could possibly be overheating. next time it starts dying see if you can touch the power head ( engine) could have a bad or blocked water pump or impellar... just a thought as I am pretty new to outboards myself

Re: 1979 Evinrude 75 hsp problem

First, be sure it's getting gas. Pump the gas bulb while the boat's running and see if the motor then runs ok. If motor's getting gas problem may well be electrical. Are the plugs wet or dry when the motor quits? Wet indicates electrical. With only one wet plug it may be that coil or a bad connection. Check that the black wires are well grounded. Check the coil insulation for cracks, fill any cracks with silicone seal as temporary measure. You can check the primary and secondary coil windings with an Ohmmeter although you can't check that way for shorts. However, you'll first need the right pages out of the right manual to tell you the correct resistance ranges. New coils can be bought cheaper on Ebay. May be the power pack, but that can't be checked without special equipment. I wouldn't buy coils before isolating the problem.

Jenlamb35 said:

My husband and I are amateur boat owners (first boat) and need some help. When we first got the boat, it hadn't been maintained well but ran. It rain great the first couple of times on the lake but the last couple of times it runs fine for a few minutes and then starts "blubbering" and loses power. My husband thinks it might be the coils but they are pretty pricey. Is there something else we can consider before that investment? Thank you.

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Re: 1979 Evinrude 75 hsp problem

Barry said he checked the motor and it's not overheating. He also tried pumping the bulb while running and it doesn't change anything. He said the spark plugs are wet after running.

He said he checked the plugs and he said two had a little spark but one had a spark that shocked him pretty hard, through insulated tools and gloves.

Does this information help narrow down the diagnosis? I appreciate everyone's suggestions and ideas. Thanks.

Re: 1979 Evinrude 75 hsp problem

Getting shocked means that coil is firing (20000 V!), don't touch the wires! If two have little spark, then first, are the plugs ok? If they're old, cheaper to replace plugs first and see how that works. Champion L77J4.

Jenlamb35 said:

Barry said he checked the motor and it's not overheating. He also tried pumping the bulb while running and it doesn't change anything. He said the spark plugs are wet after running.

He said he checked the plugs and he said two had a little spark but one had a spark that shocked him pretty hard, through insulated tools and gloves.

Does this information help narrow down the diagnosis? I appreciate everyone's suggestions and ideas. Thanks.

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Re: 1979 Evinrude 75 hsp problem

I'm sorry - I should have mentioned that Barry put in new plugs this weekend and still has the same issues. So we're probably narrowing it down to coils now? Thanks for all your ideas and help. It's good to hear that we were doing the right things anyway, even if it didn't solve the problem.

Re: 1979 Evinrude 75 hsp problem

I would check the coils with an Ohm meter.