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1988 Johnson 88 wont top out at full throttle need help.

57sailplane

New member
Hey guys,


i have a 19 foot blue fin i rebuilt the boat from trailer up as it was thrashed to heck. took 3 years to get done as i had to work on it outside and i live in hard winter area. i made some changes, one was i replaced the plastic front mount tank to an aluminum below deck tank. the fuel return neck had to be replaced so it went in the proper direction. this took some welding and cutting so tank may have residue but i did rince out with gas before i hooked up.

first time out the motor ran good but i had a over temp alarm come one. so i took it home replace the water pump. took it out again yesterday with no alarm. and it ran good for just a little bit then the problem acured.

the problem

the motor idles and runs kind of fine at lower rpm and half throttle but wont hit high rpm unless i push in the choke then it takes off. so the reading i have done says its the high speed jets in the carbs.

my qestions are can it be to much oil in the mix as i know for sure i mixed it to rich in dealing with the temp issue?

the other question since the tank might be an issue is were do i put the fuel filter as my system just has screens but no filter. can i put it between the tank and the bulb as this would be the best for mounting or dose it have to be put between the bulb and the engine?
 
On a 2 stroke like yours you must be 100% sure that the carburetors / jets are clean !-----If a carburetor is plugged than you may be starving one cylinder of fuel and most important you are starving that one cylinder of oil.-------Having too much oil does not affect the performance.-------Make sure you remove those high speed jets ( orifice ) found in the carburetor bowls for a proper cleaning.----------Those V-4 motors are excellent runners and last a long time with proper care.
 
kk, so dont run lean and to much oil dose nothing. so now were do i install the fuel filter with water seperator. can i put the filter between the tank and bulb?
 
hey guys,

well i did as you said racerone and rebuilt the carbs i removed the little orfices to clean inside as you said. bolted carbs back on yesterday. went down to get a proper fuel filter all they had at the time is an in line with no water seperater but they put one on order. i bought the in line for now.

i installed the inline fuel filter and hooked up the muffs. man she started right up and runs real good. of course i understand motor is not under a load but she seems to run real good.

i have a question though. the fuel filter is clear and i can see the fuel running through it. there is hardly any fuel in the filter when runing just a little stream is this normal?
 
Had that question all the time about 40 years ago.-----The filter / sight glass on the 60's motors would be full when squeezing the bulb.When motor was running there appeared to be little or no fuel in the sight glass.----Motor would run just fine.
 
just got home man she runs good. top end was uneventfull. after an hour or so of trolling at just above idle the motor died. so i pumped the bulb and it started right up. ran for an hour or so and did it again. so i pumped the bulb and it ran tell the end of the day. not sure what the problem is. if i have low presure at the bulb what could be the problem? air leak? pump need rebuild? or just bad fuel. it realy looked as though it was out of fuel both times..
 
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