91' 40 hp Johnson questions

airshot

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In an earlier post I ask about the squeeze ball on the VRO, thanks to all that responded. However more problems have crept up and I am hoping for the great help I usually recieve here. I took the motor out on the water for the first time tonite, started right up and purred like a kitten. After a warmup period I gave it throttle and it was extremely slow and would not get up to speed. About 19 mph on my 16 ft Starcraft aluminium boat. This is not the holiday model, but the lighter runabout model. My old Merc 40 did 24 mph.
After trying to accelerate a few times the VRO alarm started with a beep every 5 to 10 seconds. I have made up my mind to disconnect it, checked the fuel and oil lines for kinks and both primer balls were firm, so the VRO is going. When I pulled the boat out of the water and the motor was draining, water was comming out from the front of the leg where the split is for the lower unit, I see a small square hole there, is this normal?
The motor has a 12 1/2 x 15 pitch prop on it, as I don't know what comes on them does this sound about right for a fairly light 16' alum runabout?
Any adjustments that I might make or look for to address the lack of performance? Plugs were new. Any suggestions would be greatly appreciated.

Airshot
 

tashasdaddy

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Re: 91' 40 hp Johnson questions

well i suggest checking compression and spark. you are probably in for a carb rebuild.

low oil alarm is a beep every 30 seconds. beep......................beep...................

no oil alarm is a beep every 1/2 second or so.beep,beep,beep

overheat alarm is a constant beep.beeeeeeeeeeeeeeeeeeeeeep
 

airshot

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Re: 91' 40 hp Johnson questions

Thanks for the reply, the person I bought the motor from just had the carbs cleaned out by a dealer, I have the reciept. I realize that thay may have not been done properly, but the prior owner paid $130 bucks to have the carbs cleaned, according to the reciept.


Airshot
 

tashasdaddy

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Re: 91' 40 hp Johnson questions

a carb can be clean now, and some crud can break loose in the next minute, and cause problems. also until you know the oil side is working, i would premix the fuel 50:1, that way you know it is getting oil. you also may want to just disable the oil side, and continue to use the gas side, with premix, till the pump goe out. that is what is did with my 93 40.
 

airshot

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Re: 91' 40 hp Johnson questions

Removing the VRO as we speak so to say, checked plugs, one had slight discoloration other was clean. Spark jumped a long gap and compression is 150 on both cylinders. The clean plug was on the bottom, also found a pinched lower carb fuel hose. Wedged between vro pump and starter, probably not closed shut but pinched.
I also noticed a shrader air valve under a cap with a red arrow/lever around it....what is it?? Appears to come from a round cylinder with wires out the back. Thanks for the help.

Airshot
 

tashasdaddy

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Re: 91' 40 hp Johnson questions

that is the primer solenoid, it replaced the choke butterflies, in the carb, it is activated by pushing in on the key, with the key in the on position. it injects fuel/oil directly into intake manifold. the proper running postion for the red lever is inline back over the body of the solenoid. like this picture.
 

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airshot

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Re: 91' 40 hp Johnson questions

Has anyone found that a bad fuel pump would cause a lack of high speed performance ?? This 40 hp That I purchased has very little run time on it, especially in the last couple years it has not been run other than a spring warmup then put away. The VRO pump appears to be weak (low oil pressure warning) and was wondering if fuel pump portion may also be weak causing my lack of high speed performance...just thinking......
Thanks again as always !!

Airshot
 
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