johnson 25 hp problems

[powerwagon360]

hello im new to this site, found it trying to get help on this johnson.we replaced the old wore out 18 seahorse with a 1974 johnson 25r74m.we have had it for about 4 days and are working out the bugs that the other owner put in to it. First i would like to say this unit is premo! it has a reman carb (and is very clean with all the engine paint) we adj. the timing got it to stop sputering got the rich lean about right.it was runing real god ....but put the hood back on and it will sputer out and wont crank back!....remove the hood and it starts right up and runs good....put hood back on and blaaaaaa sputers out. wtf! AND this 25 dont put out the rpms the old 18 did ??? any help would be great! me and my dad are real got with cars and v8s but this 2 stroke stuff is not are flavor...lol

 

[tashasdaddy]

Re: johnson 25 hp problems

you have an exhaust leak from the lower unit into the upper section. the cowl is trapping the exhaust, with has no oxygen, to enable combustion. could be base gasket, could be gasket around the drive shaft at the water pump. or exhaust housing gasket at the lower unit.

 

[rjezuit]

Re: johnson 25 hp problems

The 25HP is also rated at a higher RPM than the 18HP, but the same CID. Rick