1981 70 hp typcial loss of power when put in gear

[stelis]

Motor is new to me. Rebuilt the carbs. Have been checking the electronics. I am getting a reading of 0 ohms on the ignitiion coil primary wire, but normal readings on the high tension leads (265 ohms). Manual says .1 plus or minus 0.05 on the primary wire. So could be an issue??? Also, spark does not seem 'strong' on the number one cylinder...

Back to the carbs, with the motor tilted up I got alot of gas spilling out under the cover. This doesn't sound normal to me, or is it?

Thanks.

Steve

 

[Fisherball]

Re: 1981 70 hp typcial loss of power when put in gear

My '81 70 hp does not leak gas when tilted forward. I don't know much about carbs but it sounds like something is sticking open inside yours. If nothing else disconnect the fuel line whenever you tilt it.

I love my motor! 70 horsepower from 49 cubic inches, that's like a Chevy 350 with 500 horsepower!

 

[stelis]

Re: 1981 70 hp typcial loss of power when put in gear

I should have been more specific about the leaking gas - it is actually residual gas in the carbs as I always disconnect the gas line after us. It's not alot of gas, just something I noticed.

Thanks for your response, though.

Steve

 

[jtexas]

Re: 1981 70 hp typcial loss of power when put in gear

welcome to iboats, I have the '79 vintage, pretty much the same motor.

the gas leaking out with the motor tilted means either the bowl gasket is leaking or the float valve isn't shutting off. could be misadjusted float height, or maybe you forgot the o-ring under the valve seat? did you install new kits with your rebuild?

You can test valve operation by blowing through the fuel inlet -- with the carb held upside down, no air should pass; right side up should be very little resistance. I recommend draining the carb bowl first -- premix is an acquired taste.

0 ohms is better than 0.1...most meters show something like .0L for open circuit.

But better to test the ignition with an inline spark tester (couple bucks at autozone) -- set the gap to 7/16", clip it to the block, attach the plug leads (one at a time) and look for a strong blue spark while cranking.

Also a compression test is in order. Look for PSI to be about equal on all three (within 5 or 7%). Upwards of 100 is good -- mine is 121-120-120