I have a mid 80’s model Johnson 70hp on My BW Sport. It’s been stalling when I give it any throttle over 20%. I’ve bought new plugs but the problem persists. It won’t go over 6 mph on the way shrimping, but on the way back (after a few hrs running) it will sometimes let me run it full speed.
I’m no mechanic but it seems like I need to get my carbs cleaned or possibly rebuilt. What can I expect to pay for this service on a 80’s model Johnson 70hp?
1985 Boston Whaler Montauk “17”
1982 Boston Whaler “15” Super Sport
That is exactly what my 1995 Johnson 88 spl did when my water separator filter was full of water. The filter would have enough clear filter area to let a little gas through and I could run up to about 1800 rpms. If I tried to get up on a plane, she’d starve and either slow to a crawl or shutdown… only to restart easily.
I’d check that filter. If you don’t already have one, I’d also put a filter with a sight bowl on it. Then, when you see a little water in the bowl, you drain it off and the filter never gets full of water.
And, if you’ve been sucking water through your filter (they will eventually saturate and let water through) you may need a carb cleaning.
If you have a water separator filter, I’d change that first and see if the carbs won’t behave themselves with a little good fuel.
'Had the exact same problem with a friend’s boat a few weeks back. He had a sight bowl but had not drained it in a long time. 'Drained the sight bowl. Motor picked up and ran like a top. Caught several nice reds and a 21" trout. Sight bowl with a drain saved the day.
If after tending to the filter, you still have problems, then maybe its time to look at the carbs. I rebuilt my own. 'Not terribly hard. I used a digital camera to document every thing before I took things apart. Get a SELOC manual for your motor and follow the instructions.
17’ Henry O Hornet
26’ Palmer Scott
great advice. . Will try it this evening. . probably along with spraying some Carb/Choke cleaner in there while the engine is running.
1985 Boston Whaler Montauk “17”
1982 Boston Whaler “15” Super Sport
spraying carb and choke cleaner in it while its running will not help the carbs
changing the filter may help, but chances are, based on your description, the junk has made its way into the carbs
carb rebuild…
$159 for the first one
$79 for each additional
I’m now at www.teamcharlestonmarine.com