carb adjusting 1981 90hp v-4

[81_chapparel194]

Re: carb adjusting 1981 90hp v-4

The idle air bleeds are the jets between the two throats on the face of the carb. Metricwrench is correct, just follow the factory diagram and insert the jets they way they appear on the exploded parts diagram.

ok after removing the carbs today when i got in from work, (man i swear i can do this in my sleep, i had the carbs off and on the work bench in 20 min) i dissasembled the carbs checking the # on each jet as i removed them and found each jet was in the perspective place. whoa i must have been more dilligent than i thought OR got extremely lucky. because i sure dont remember taking note of the numbers on them the first thousand times i tore it apart. but according to the parts diagram on brp parts diagram they were all in exactly the right places. idle jets were #29 mids were #35 idles being behind the top screws on the lower carb bowl. mids being in the upper throat of each carb. and of course the mians were in the lower screw holes (cant mistake those different thread pitch). i was ready to give up when i decided to blow thru the mid jet passages with very low compressed air. actually from a 12 volt dc inflator with a conical shaped adaptor used to inflate beach balls and water toys. i noticed on one of the passages i was getting very restricted air flow from the other end of the passage. all the other 3 were fine free flowing. so after a few seconds of blowing air thru that restricted passage i decided to spray some carb cleaner and see if that would help. well no luck. so then i had a hair brain idea. (i know dangerous for me) lol i found a fine piece of single strand wire that just would fit inside the smallest end of the jet that ran from the top of the carb down to the bowl. i fished it thru the passage ever so slightly until i saw what appeared to be a real slender piece of string maybe coming out of the bottom. well running the wire thru several times spraying carb cleaner thru the passage and alternating low pressure compressed air i saw little particles of what ever the blockage was coming out. so i kept cleaning and spraying and blowing air thru until i was sure it was clear and the pressure felt equal coming thru all passages. and to be safe and since i was already into the carbs i just went ahead and did all passages the same way. luckily none of the others showed any sign of blockage. i decided it was time for a cold adult beverage so i re assembled both carbs put them inside ziploc bags and left them lying on the work bench until tomorrow. i am now kicking back enjoying a cold beverage and already itching to splash the ol girl and see if my problem is solved.... i keep kicking myself for missing this the first time i soaked and cleaned the carbs. although as my lovely admiral said "baby maybe it sucked it up very soon after you re assembled and started it up" she is soo confident in my work. thats why she is my admiral..

 

[wayneo99]

Re: carb adjusting 1981 90hp v-4

im glad to see you found something that could be the cause of your issues. keep us posted

 

[81_chapparel194]

Re: carb adjusting 1981 90hp v-4

im glad to see you found something that could be the cause of your issues. keep us posted

you arent as glad as i am. ha ha i have been pulling my hair out trying to figure this out. i will know saturday if this fixed the problem or not. i sure hope so. because i dont know of anything else to try. it has baffled myself and two other evinrude wrenchers that was wrenching when this engine was new. although everyone kept saying fuel related myself included, we just couldnt find where it was after inspecting/testing/checking everything fuel related. three times over. but we were all under the assumption the carbs truly were clean considered i soaked them for 24+ hours in carburetor cleaner and blowing thru all passages. but i do realize the very first squeeze of the bulb after the clean carbs went on could have introduced this foreign material to fresh clean carbs. i just dont understand where it came from. it passed thru the filter screen on the pick up tube in the tank, then thru the in-line fuel filter (since removed thinking this was my problem maybe an air void) then thru the screen on the pump. but it honestly looked like maybe a string from the center of the fuel hose plies. ( ya know the chord that runs the length of the fuel line to keep from the line pulling apart) but i dont know exactly where it came from or what it was. it may have even been a thread of teflon tape, however i dont use it BUT i DID see some on the gas pump nozzle at my local gas station (ethanol free) where the hose screws onto the nozzle.. perhaps a small piece made it into my tank through 2 screens and a filter. things that make you say hmmmmmm. and as far fetched as it is STRANGER things have happened.

 

[wayneo99]

Re: carb adjusting 1981 90hp v-4

I found a small sliver of gasket material in the bowl of one of my carbs. turns out it was from the gasket of the fuel pump that was eaten up by the ethanol gas.

 

[emdsapmgr]

Re: carb adjusting 1981 90hp v-4

The original fuel hoses on that 1981 engine are not rated for handling ethanol fuels. The walls of original hoses will break down over time. Usually the carb jets accumlate bits of black fuel hose that's been eaten away from the inner hose walls over time. First time I've heard of a string! Solution, buy replacement fuel hoses-any factory replacements are 2013 fuel rated. It's a good idea to monitor flow through carb passages. An aerosol can of Gumout, sprayed through a carb passage should be monitored for the outflow on the outlet of that passage on one carb. Then spray that same passage on the other carb. Note the spray flowing through that passage: compare the two, the outflow flow should be the same. Repeat that step back and forth between carbs, comparing outflow spray to make sure all passages flow at the same rate. You'll find a restricted passage fairly easily with this procedure.

 

[81_chapparel194]

Re: carb adjusting 1981 90hp v-4

The original fuel hoses on that 1981 engine are not rated for handling ethanol fuels. The walls of original hoses will break down over time. Usually the carb jets accumlate bits of black fuel hose that's been eaten away from the inner hose walls over time. First time I've heard of a string! Solution, buy replacement fuel hoses-any factory replacements are 2013 fuel rated. It's a good idea to monitor flow through carb passages. An aerosol can of Gumout, sprayed through a carb passage should be monitored for the outflow on the outlet of that passage on one carb. Then spray that same passage on the other carb. Note the spray flowing through that passage: compare the two, the outflow flow should be the same. Repeat that step back and forth between carbs, comparing outflow spray to make sure all passages flow at the same rate. You'll find a restricted passage fairly easily with this procedure.

all fuel lines were replaced end of last season because they were showing wear and i was unsure if any were cracked sucking air.

 

[81_chapparel194]

Re: carb adjusting 1981 90hp v-4

ok sorry for the long reply/follow up. but this past weekend i was able to run the boat. and the boat STILL has the same problem. i was thinking maybe now a fuel pump problem but it idles perfect and the bullb stays hard. i dont have to re prime the bulb thru the day. i tried but bulb was hard and pumping it doesnt help the situation. but pushing the key in to activate the electric choke/prime does help.

 

[81_chapparel194]

Re: carb adjusting 1981 90hp v-4

ok for any interested parties I have seemed to figured out and corrected the problem.. or at least I took it to the lake today and ran it for about 2 hours and it never stalled once. the problem....wait for it....wait for it...... the dadgum thang was idled to low. I cranked the idle up to where it was about 950-975 rpms in the water and walah no more stalling. I had found where the factory recommended idle specs were 1k rpm's in the water. in neutral. so I got it up to 950-975 and no issues now. evidentally the engine didn't have enough idle fuel to get over the initial hump of the torque of the prop going into gear. now when I drop it into gear at idle speed it actually moves. before when it would run and not stall it would barely move in idle forward. now im like whoa im getting somewhere. so happy happy happy ending for me.