Yeah, from a financial point of view, we can now class carbs for small engines as 'disposable'.

A year and a half ago, I bought a Tohatsu 5HP four stroke for my dinghy.... it replaced an 8HP 2 stroke Merc (actually, made by Tohatsu), which had been rather finicky, and which was simply larger than I needed and very heavy, to carry.

The Tohatsu worked great, the season before last, as well as last season. This year, however, when I first used it, it wouldn't idle properly... it would either stall, race, or run with variable speed in idle. In additional testing, it was working fine at any throttle setting while in gear.... but it just wouldn't idle correctly.

I immediately suspected that the low speed (idle) jet was clogged or gummed up. My usual 'decommissioning' was to run the engine dry, and then store it in my office during the winter; I wasn't in the habit of using any fuel conditioner; in my previous 30 years of experience with several small outboards, it was never a problem... even after the gas started to include 10% ethanol.

Upon suggestion from fellow boaters at my marina, I bought some Seafoam, and added a fair amount to a fresh gallon of gas, and ran the engine for several hours, over the course of two days. While it ran fine at any speed in gear, the Seafoam additive did not result in restoring proper idle.

So, what to do? Online, I found several videos illustrating the procedure for removing the carburetor... unfortunately, none illustrating how to fully disassemble it. I pulled the carb off, and opened the bowl... and it was clean as a whistle, as if it was brand new. Evidently, if the low speed idle jet is clogged, nothing else indicates any evidence of 'varnish' or 'gelling' from the fuel. Not having a shop manual, OR a local source for small parts, I didn't attempt to disassemble it further... I put it back on, and it's running the same: fine, at speed and in gear, but not idling consistently.

A boating friend recommended that I take it to a place in Warren, RI, which, he assured me, had an excellent reputation for repair work (there are VERY few Tohatsu service dealers in my area, and this one was not the closest, but I was told on the phone they could turn it around fairly quickly).

The fellow who owns the place was a grizzled old guy, sitting in some well-worn chairs in the front showroom, and I was able to sit down and have a long conversation with him, learning a great deal about carburetor problems. The first piece of information I got was disappointing: he said that they could NOT turn it around quickly, at all, owing to the backlog of service orders.

He confirmed my diagnosis of a clogged low speed idle jet... but what he had to say about clearing it was NOT encouraging. Basically, the low speed idle circuit is sealed, and to fix it, a fitting would have to be first drilled out, followed by replacement with small parts that are not included in the usual carb repair kit (they probably would have to be ordered from a Tohatsu distributor). Before replacing those parts, the carb would have to be subjected to an ultrasonic cleaner, as well.

From an economic point of view, it actually makes no sense. Their labor rate is $150/hr, and even though it takes very little time to remove and reinstall the carb, the cleanout takes well over an hour... add to that, the cost of parts.

However, a complete replacement carburetor, via Defender, is $154 plus shipping.... probably less than the cost of a carburetor cleanout at a service dealer.

This fellow is also a Honda dealer, and services a lot of Honda lawnmowers and portable generators. He tells me that the Honda replacement carbs are so cheap.... as little as $10, for some small power tools... that they don't even bother to try to clean them, it's simply not economical... they just replace them.

So, I bought a replacement carb from Defender, with overnight delivery... for about the same price as having it serviced, just three weeks sooner. I expect it tomorrow. The fellow told me that it should run fine, upon installation... the only thing I might need to do is adjust the idle speed (the air-fuel mixture screw is factory set and needs no tuning).

Of course, this does cause me to consider how I treat the fuel during the season, and how I decommission the engine in the fall. I'm thinking now that the last tank of fuel, in late September, should probably be a can of 'True-Fuel' (expensive, but there's no ethanol in it), mixed with some Sta-bil or Seafoam, before running it dry for the winter.

All in all, it does seem rather amazing that the carburetor has become a disposable item.