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1994 115 Johnson slow midrange acceleration

fishhead1500

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"I have a 1994 90 dg. crossflo

"I have a 1994 90 dg. crossflow . Powerhead was rebuilt about 2 years ago . I have not let it sit for long periods of time . It had a sneeze after it was overhauled and died alot at idle but otherwize ran strong. I took it back to the shop and after some "syncronizing" the first trip out it seemed to run good and idled better. Next week I took it out with extra people in the boat and was forced to run at low speed for an extended time due to weather conditions. I noticed after a while I could open the throttle all the way and I was barely accelerating. I checked the plugs and they were wet. I have since changed the plugs a few times. It still idles great and once it gets going it runs really well after it planes. If you have to run at slow speed for any distance you open to full throttle and you wonder if it is going to do anything and then it will gradually accelerate and finally it will take off and run fine. Plugs run pretty wet and dark.I am mixing fuel 50/1. Shop that rebuilt it removed VRO. They charged 220.00 to "adjust it" last time while powerhead was still under their warranty. I want to try and fix it myself. Thanks , fishhead 1500"
 
"If you want to fix it yoursel

"If you want to fix it yourself the best thing to do first is buy a manual.

Are all the plugs wet?

Puchase a spark tester, I like the inline version that plugs into the spark plug cable then onto the plug, that way you can watch the spark while it runs. (there's cheap too.. )

Next you'll need a timing light, because you need to verify the timing at idle, in N and in Gear, and at Max Throttle.

Do you have a Fuel Water Separator ? If not.. Get one. Keep your tank full if you can, lessens the ability for it to gather water, which will cause the problem you are having.

Some shops like to run their own fuel, ask your shop if they do that and if they checked the quality of your fuel, You can check yours too.. by pouring some into a clean clear glass jar.. let it sit for about an hour.

some things to think about for you."
 
"I have a manual and have alre

"I have a manual and have already checked the max throttle timing (as posted by Joe Reeves in 02) using the spark tester set at 7/16 and max timing is good. Compression is 100,120 ,120,120. I have a 30 gallon tank and no water seperator. I have run a few fill ups through this tank since the problem started . I am going to do a seafom decarb after work this evening to see if that helps with the low compression on #1 cylinder. I have never gotten the last gallon or two out before refilling tank and we have 10% ethanol where I live. I guess after reading your reply maybe I should run it on a remote tank to see if that changes anything. I guess I should look into a water separator as well. Thanks alot for your help. This site is great. RH"
 
Ran the 16 oz. of Seafoam in a

Ran the 16 oz. of Seafoam in about a gallon of gas allowing it to cool down after 15 minutes as per another post. With engine warm my compression readings were from 95 on the low cylinder to about 115 on the highest. I can still see carbon on top of pistons. I guess my next step is to try a portable tank with fresh gas to see if there is a problem with my fuel /tank/ or hose. Any suggestions appreciated.
 
The 'low' cylinder is

The 'low' cylinder is out of acceptable range. I'm afraid You may end up with a tear-down to correct that issue.
 
This motor has been overhauled

This motor has been overhauled at least twice. It appears to have always been a saltwater motor . There is a good bit of corrosion on the steering bracket etc.. I hope I can just run it a while and get some use out of it before it dies. I was hoping that if there was a stuck ring the decarbing might help.Thanks RH
 
"' Shop that rebuilt it re

"' Shop that rebuilt it removed VRO. They charged 220.00 to "adjust it" last time while powerhead was still under their warranty. I want to try and fix it myself. Thanks , fishhead 1500'

Seems to be a shop to avoid in the future, I,m afraid they have missed the reason for rebuilding last time, and You are back to square one.
However I doubt You will be able to 'cure' it without tearing down! At least take off the head and inspect the cylinders/pistons/heads for damage."
 
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