1984 70hp johnson no thrust power

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veteran81

New member

• Jan 20, 2016

• #1

I need help my johnson runs out of the water but it will not run in water, it stalls. Carburadors have been Re built. Any suggestions?

Thanks,

Veteran81

 

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racerone

Gold Medal Contributor

• Jan 20, 2016

• #2

Very common issue.--------Very common for folks to pick on the carburetors first too.----------On the trailer the motor does not have to do any " work " and will sound fine on 2 of 3 cylinders.------------------So check compression first.------Then see if you have spark on all 3 leads.---Does spark jump a gap of 3/8" , yes or no ?

 

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veteran81

New member

• Jan 21, 2016

• #3

First of all let me thank you for taking interest in my problem.

Compression is 128 on all 3 pistons. I didn't check for spark. I just removed the lower unit to change water pump and changing seals. I'll putting it back together this weekend. Based on your opinion what could be wrong?

 

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kimcrwbr1

Banned

• Jan 21, 2016

• #4

Check and adjust engine sync between the timing advance and throttle opening! Do the carbs open at exactly the same time? Exactly how are you adjusting the slow needles?

 

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racerone

Gold Medal Contributor

• Jan 21, 2016

• #5

??-----Are there slow speed needles on the 70 hp model or just on the 75 hp model ?

 

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kimcrwbr1

Banned

• Jan 21, 2016

• #6

Using the year it shows slow needles for the 70hp probably best to have the model number to confirm?

 

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kimcrwbr1

Banned

• Jan 21, 2016

• #7

racerone said:

??-----Are there slow speed needles on the 70 hp model or just on the 75 hp model ?

Click to expand...

Good call looking closer you are correct were the slow speed jets cleaned properly when the carbs were rebuilt would be the next question?

 

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veteran81

New member

• Jan 21, 2016

• #8

kimcrwbr1 said:

Good call looking closer you are correct were the slow speed jets cleaned properly when the carbs were rebuilt would be the next question?[/QUOTE

J70TLCO is the motor number. I know nothing about mechanics I'm just learning. But I do want to ride my boat.

Click to expand...

 

papyson

Outstanding Contributor

• Jan 22, 2016

• #9

I don't see where you checked the spark with a tester as racer suggested...

 

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veteran81

New member

• Jan 22, 2016

• #10

I haven't checked the spark. I don't understand how to get he measurement of 3/8??? how do I figure this out?

 

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kimcrwbr1

Banned

• Jan 22, 2016

• #11

http://cgi.ebay.com/ebaymotors/Igni...761901?hash=item1c349c976d:g:Jt4AAOSwm8VUvwdu
I just bought one of these adjust the gap and clamp it to a good ground. You can do the same with a plug wire cut in half and staple a gap on a board. Another way is to stick a screwdriver in the plug wire and hold the shaft around 3/8 inch from a good ground just chip a little paint off a sharp corner somewhere. You can buy one at any auto part store.

 

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veteran81

New member

• Jan 23, 2016

• #12

Okay, I'll start working on it on Sunday morning, I'll let you know what the outcome is.

Thanks.

 

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veteran81

New member

• Jan 23, 2016

• #13

Okay, I'll get on it Sunday morning and let you know the outcome.