I know, I know....this is old hat for most of you, but had to post this as a thanks to all that have posted before regarding this subject. Also as a reference for those that may have a similar problem.
Between the seach feature, the tech help regarding the secondary (depression chamber), odds and ends of posts in this forum and the FSM... I was able to solve the problem I was having.
1988 SWB 2.6 4cyl. with Mikuni
Had hesitation problems from the time I bought it (almost a year). Would hesitate from a dead stop unless you had the pedal gas pedal to the floor..and even then it would want to stumble. Sometimes it would feel like you were on a mechanical bull.
Over the course of time I had just dealt with it. Not my daily driver...used for fishing, BBQ events and tailgate parties. Love to drive the thing so...it was a price to pay. A few months ago I picked up a used Mikuni off of a parts car. A student reference manual on a '85 carb etc. The previous owner had a set of FSM's and a Haynes book.
Annnnyhow, turned out to be a few things that eventually led to the solution.
The hose from the top of the depression chamber had a crack. Replaced that. Also "tested" the diaphragm by manually moving the spring up then holding a finger over the hole and removing finger to allow the diaphragm to release.
Replaced fuel filter. No idea how old it was but the clamps were rusty and the filter just looked old.
The carb had two blind caps over some apparently extra vacuum ports that may serve a purpose on another application. Those each had a crack in them. Replaced with the ones from the donor carb.
All other hoses looked good.
Studied the donor carb and located the jets. Cleaned the carb REALLY good (spray cleaner). Then cleaned it more while the engine was running. Revved the engine and cleaned those jets. Shut it down, cleaned the carb again. Cranked it up again and cleaned the jets again while running.
Shut it down for a bit and took it for a spin.
WOW!!! It runs fantastic! No noticeable hestitation from a dead stop. Cruises right up through the gears.
Took it for another spin a couple hours later through a decent amount of traffic/lights. Fantastic.
I was *this* close to pulling the carb and replacing the depression chamber from the donor as a last resort. Who knows... that may be an option later.
Anyway...hats off to the forum. I don't post much but I visit daily it seems.
Thanks all!
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