Could I have dropped a cylinder?

FSUDTD

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Sep 15, 2004
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HEY FELLAS,<br /><br />I HAVE A 1988 40HP JOHNSON THAT UP UNTIL THIS WEEKEND HAS RUN GREAT; TOOK IT OUT SATURDAY AND SHE RAN PERFECT, BUT THEN TOOK HER OUT AGAIN SUNDAY AND SHE RAN REALLY FUNNY. STARTED RIGHT UP ON SUNDAY BUT THEN WHEN I WENT TO GET UP ON PLANE SHE WAS VERY SLUGGISH AND SEEMED TO MISS EVERY ONCE IN AWHILE AFTER GETTING ON PLANE. FIRST THOUGHT WAS THE FUEL INTAKE; I GAVE THE BULB A COUPLE OF PUMPS AND SHE SEEMED TO PERK UP. THIS DIDNT LAST LONG HOWEVER AND ON THE FINAL DECENT HOME WHILE THE SHIFTER WAS STILL IN THE WOT POSITION, SHE DROPPED OFF PLANE AND WOULD ONLY GO ABOUT HALF SPEED. THE LAST COUPLE OF TIMES I STARTED HER OUT ON THE WATER SHE WAS VERY HARD TO TURN OVER AT FIRST LIKE THE BATTERY WAS OUT OF JUICE, BUT THEN WOULD ALL OF THE SUDDEN FIRE RIGHT UP. GOT HOME AND WENT TO FLUSH HER OUT AND SHE WOULD BARELY TURN OVER. CHECKED THE BATTERY AND IT WAS AT 12V SO ALL GOOD THERE. SEEMS LIKE THERE IS A SIGNIFICANT AMOUNT OF RESISTANCE SOMEWHERE RESTRICTING THE ENGINE FROM TURNING OVER FREELY. PLAN TO PULL THE PLUGS AND SEE WHAT I SEE; ANY SUGGESTIONS AND/OR ADVICE WOULD BE GREATLY APPRECIATED.<br /><br />THANKS<br />BRANDON
 

Walker

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Jun 15, 2002
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Re: Could I have dropped a cylinder?

Sounds bad. Do a compression test.
 

fireman57

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Re: Could I have dropped a cylinder?

And please don't yell at everyone in caps. Post your test numbers. Sounds like it got hot.
 

FSUDTD

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Re: Could I have dropped a cylinder?

Excuse the delay between posts; just completed a compression test: got 120 psi and 115 psi on the two cylinders. I also checked the spark, and it seems to be sufficient. What next? Any suggestions or self tests would help.<br /><br />Thanks
 

dajohnson53

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Re: Could I have dropped a cylinder?

Two things this fairly non-mechanical guy would try first:<br /><br />Check the fuel supply, especially at the filters and the pickup of the tank. This could have caused your engine to crap out after running well for a while.<br /><br />Charge up the battery again, and make sure the cells have the right level of water, correct specific gravity AND clean the posts and all connections. The hard starting could be as simple as the battery not fully charged (by the way, it should be higher than 12 volts at full charge - not sure, but I think it's closer to 13 volts), or dirty posts or connections.<br /><br />You could also have your battery tested at an autoparts store (e.g. NAPA) they will usually load test it free. A battery can look good but be bad or getting bad enough to cause hard starting.<br /><br />Hopefully others will chime in with more and better suggestions, but these are two you could find to be productive.
 

dajohnson53

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Re: Could I have dropped a cylinder?

PS: also on my short list of first things to check in the fuel system (including the filters and pickup) is look for water in the tank. Again, something that can cause performance to go down after it's worked well for a while. If you have built in tanks, put in an in-line water filter. If you have portable tanks, try completly emptying them and drying them out and using fresh fuel.
 

JB

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Re: Could I have dropped a cylinder?

When was the last time she got a new impeller, FSUDTD? I agree with fireman. I think it got hot.
 

FSUDTD

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Re: Could I have dropped a cylinder?

well fellas, im sitting here humbled as i type this, but hopefully it will help someone else down the road. After checking the voltage at the starter (6v) I decided to try and charge the battery whether it needed it or not. After about an hour, i got ancy and had to give it a whirl. Fired right up first try and never missed a beat. Boy do i feel dumb. Thanks so much for all your suggestions. I do plan to test the battery and either get another or have the charging system checked as well as replace my fuel bulb as it seems to have developed a leak. Please excuse my ignorance throughout all of this.<br /><br />thanks,<br />brandon
 

fireman57

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Aug 24, 2004
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Re: Could I have dropped a cylinder?

Once it is running it should not be sluggish even with a low battery. Something else is going on too.
 

FSUDTD

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Sep 15, 2004
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Re: Could I have dropped a cylinder?

fireman,<br /><br />I do realize that and think that a leaky gas line at the bulb might be the culprit, however am open to suggestions.
 

dajohnson53

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Apr 28, 2004
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1,627
Re: Could I have dropped a cylinder?

A complete new hose and bulb only costs around $10. If it's old or looks at all bad, it might be worth replacing. A cheap fix if it fixes it, something that needs to be done anyway if it doesn't.
 
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