1990 90hp evinrude 2 stroke question

[bob ledlow]

the motor wont get up and run w/out holding in choke buttton. i went thru the carbs. bulb stays tight when running. i can take the linkage off and run up rpms on each carb individually and hold the rpms steady but when i put it in the water it acts like its starving for fuel. help please!! thanks- bob

[wilde1j]

Check all gas line for air leaks, make sure tank is vented properly, pickup screen is clean, anti-siphon valve is working correctly, pickup tube isn't cracked, fuel pump output OK, primer bulb is OK.

[SparkieBoat]

try pumping the bulb and see if that helps. also do a spark check on each cylinder with a spark gap tester set at 7/16"

[bob ledlow]

ok- i installed new tank and fuel line. new plugs gapped correctly. when its running the bulb is hard and when i pump it, it has no improvement. the fuel pump seems to be working perfect. i also unhooked the carb linkage and opened the throttle on each carb individually and they held their rpms perfect. but in the water it acts like its starving unless the choke is held in? im lost on this one. any other ideas??
thanks- bob ledlow

[Xcusme]

It would seem that your carb(s) have a problem with letting enough fuel through when called for...

A complete carb cleaning would be the next move.

[AlanR]

I would have recomended right from the start a basic carb clean

[bob ledlow]

i thought the same thing. carbs were rebuilt 1 yr. ago. understanding that dont mean anything with this new fuel i tore them apart again. everything looked brand new. i thouroughly cleaned everything anyway with tip cleaners and carb and choke spray. do you guys think it needs to be vatted anyway??

thanks- bob ledlow

[AlanR]

how are your reeds?

[bob ledlow]

everything looked good and clean. it seems that the consensus is that this must be a carb issue somehow. i may have to take it to a better carb person. it just seems odd that it will hold great rpms when i manually open the butterfly's hooked up in the garage, but wont in the water.

thanks- bob ledlow

[emdsapmgr]

Any engine will run on 2-3 cyls on the trailer. It's a different matter when it is in gear, and the exhaust is 2 1/2 feet under water. I'd check for a fuel restriction. The primer hose ball should get hard when you pump it up to start the engine when cold. After running, the bulb should get soft, but not collapse. It's not normal to stay hard when the engine is running. Any carb cleaning requires complete carb teardown and the use of some type of aerosol carb cleaner-blown through the passages in the carb body. You can't see any dried fuel in these passages unless you check the spray pattern of the carb cleaner out the passageway exit hole.

[kenmyfam]

It only takes one microscopic piece of something to ruin an otherwise good carb set up. Another thorough cleaning and rebuilding is in order in my book !!!

[tboydva]

I just went through the humbling experience of figuring out I put one of the top gaskets (with the channels) on upside down. If you tear down your carbs again, might be something to double check. I found out the hard way that the engine will idle perfectly, but not spin up under a load (no fuel channeled to the carb with the gasket incorrectly seated).

[SparkieBoat]

it is easy to get a motor to rev up out of the water...also it is not a good idea to rev real high on the muffs, I try to keep mine under 2K...sounds like a definite carb problem..maybe floats out of adjustment or needle valve clogged.

[ALARVR]

That happened to my 88SPL. The red fuel tanks deteriorate and the crumbly red plastic got into my carbs. It would only get up and go when pushing the choke in. It was a clogged idle jet. I took the fuel line off my fuel pump and shot carb cleaner in it and ran on muffs multiple times. Got it in the river under load, beach it, shoot more carb cleaner, repeat. Then one time under a load on the river it just came loose, and ran like a top. I also had a new tank, and new gas etc...My friend also has an 88SPL. his did the same, but it was worse than mine. it had been sitting up for years. He had to break his carbs down, he used a needle tool and pushed a piece of hard varnish out of his jets that would never have "broke free".

[SparkieBoat]

carbs are just not that hard to remove and disassemble and clean..make sure to clean needle valve area and check floats.

[wilde1j]

Have you tested the fuel pump output?

[outlaw241]

make sure your nozzle gaskets are in good shape.if they are the least bit buggered up it could be sucking air above the float level.