Losing Power

[Apachi]

Hi i'm looking for assistance in solving a problem with my 235hp V6 Johnson outboard....while it's on land it's starts fine, and get's sufficient Rpm, but when i launch the boat i only get up to 3000 Rpm and then it starts to drop to about 1500 at full trottle.....i changed the spark plugs and the old wires that was corroded

this is my first boat and the guy i bought it from said it wasn't in use for about 6 months, but when i drove it to where i parked my boat it worked fine reaching 6500 Rpm and suddenly droped to 3000 and then started having the problem described above

any suggestions, Apachi

 

[rndn]

Re: Losing Power

Never run your motor higher than 1500rpm's unless it is in the water.

 

[tashasdaddy]

Re: Losing Power

what year and model #. sitting 6 months could have picked up crud in the fuel system. have you check compression, and spark, get a baseline, then check when it messing up.

 

[Apachi]

Re: Losing Power

it's a 1979 model 235TL79 or 235TXL79, i checked for the spark and getting it but not to strong, i didn't check the compression but will do that, i was thinking if the power packs weren't good if it would cause that problem

 

[HighTrim]

Re: Losing Power

The spark on that motor should easily jump a 7/16 gap on the inline tester with a bright blue ZAP!! If not there is something wrong.

I would imagine a carb bath and rebuild, along with a water pump rebuild is in your near future.

Post the compression numbers when you can.

 

[Solittle]

Re: Losing Power

Take your time and troubleshoot before throwing parts at it. get the OMC shop manual specific for your engine if you don't have one already.

 

[Apachi]

Re: Losing Power

thanks for the assistance i'll keep you all posted on the progress, thanks again

 

[Apachi]

Re: Losing Power

i guess it was a compression problem, i opened the engine block cover to check to see if anything was wrong with the pistons inside and to my suprise the head gasket was blown and the cylinder was badly bruised and scraped, and the little rubber to control the flow of water worn out so it blocked the flow of water to one of the cylinder which caused the whole thing in the first place so the cylinder had a little crack and water was getting in...guess i'll be visiting the Machine shop to get that fixed