BF25 Jet Problems

Hi folks and greetings from Dundee Scotland,

As i`ve just joined then i thought i`d say Hi first off.

I own several outboards 3 of which are honda 4 strokes. An old 10hp, a 1997 BF25 and a 2000 BF50.

I bought myself an ultrasonic cleaner the other day and it arrived this morning so i thought i`d strip the carbs off my 25 as it`d been struggling midrange and at times could only get to WOT by blipping the choke on and off.

Anyway, i stripped the carbs down and gave them a good go in my new toy and everything came out really well. The problem is that when blowing the parts out with carb cleaner then i noticed two of the jets were cracked as they were spraying fuel in different direction than they should`ve been.

My question is what effect would this have on the running of the engine?

Cheers, Matt.

Forgot to add that the jets that are cracked are number 19 on this diagram http://www.boats.net/parts/search/H...1000001 TO BAJL-1999999/CARBURETOR/parts.html

Looks like you found your problem.

The cracks will cause the problem that you are having. The jets carry fuel to the upper part of the carb into the idle and transition chambers.

I would change all three of them. If two are cracked, the third is probably not far behind.

Mike

Hi backatchya Matt from beautiful sunny Southern California! And welcome aboard the forum.

Those tubes DO have tiny little holes in them so I hope you are actually seeing cracks and not referring to the spray coming out of those little holes. If they are indeed cracked, (which they do quite often) they will cause you running problems and should be replaced as Mike said. Don't neglect to be VERY careful with that little Oring at the top. Use a new one of those each time the tube is pulled and lube it prior to CAREFULLY inserting the tube into the top of the venturi.

Cheers guys and i was going to be ordering 3 new ones today. They`re definatly cracked as the ultrasonic cleaner has got them so clean that i can both see and feel the cracks on them. I`ve overhauled hundreds of bike carbs over the years as i was a bike mechanic but have only been playing with boats and outboards for a couple so still loads to learn.

Another quick question is about the dashpot setting, I`ve got all the honda manuals and studied them carefully but i can`t get anywhere near the gap that it says in the manual with the roller just resting against the arm. Any advice on what the gap should be or a gap that would work ok? I`m not entirely sure what the dashpot`s job is but i take it`s to reduce the effects of sudden throttle changes?

Cheers, Matt.

I'll bet hondadude will answer your question about the gap setting. I've never worked on one of these either so he's the "man". Yes, your assumption about the dashpot being a damper is correct. They keep the engine from "gagging" if the throttle is released too quickly. They were a common item on carbureted autos back in the day.

It is very difficult to actually measure that gap....

In reality, adjust it so that you can just see light through the gap.

That's it.

Mike

I did think an air gap between the assister plate and throttle opener cam, 6.3mm (0.25in) as the honda manual states was a bit much. I couldn`t get mine anywhere near that wide even using feeler gauges and the body as far up it`s adjustment as it`d go.

Cheers, Matt.