102 doesn't accelerate over half throttle.

[Eugrasse]

Hello, my 102 with Amal two jets runs smoothly up to half throttle, if I accelerate it does for a while than it reduces speed and power , to avoid it stops I have to reduce throttle, than it runs smoothly at reduced speed. I checked the fuel line and fuel arrives properly to the carb, therefore I presume the problem is in the carb, I'm wrong? Any suggestions?

[Keith.P]

Not necessarily a carburettor problem.
It could be leaking rings or crank seals.
What motor is it.

[Oyster 49]

Is it fuel starvation, you might be getting fuel but is it enough at higher speeds. Clean the entire fuel system, tank, tap, filters and float bowl, check jets are clear.

I had a similar problem a couple of years ago, fuel was arriving in the float bowl, but the engine died as soon as the throttle was opened up, after stripping everything down, I found nothing until I finally soaked the petrol pipe in paraffin and flushed it through, all sorts of crap came out! There as just enough fuel flowing through the pipe to fill the float bowl, until the throttle was opened, then the demand could not be fulfilled..

Also do you have the correct prop? If the prop is incorrect you might be trying to drive a prop that is too coarse pitched.

[Eugrasse]

Engine is 102 TC80928L, with Amal Twin jet, the propeller is in the picture attached. Fuel tap and fuel line are not original,I'm waiting for the parts I bought to replace them. Is it possible to remove the jets without the proper tool?

[Nudge]

Is it possible to remove the jets without the proper tool?

yes and no!
you can make a tool to do the job or if you have a small socket that will fit you may get away with it all depends how tight they are.
if you have ordered the tool use that when it turns up.

the prop shouldn't be the problem.
My bet is the jets need cleaning.

[headdownarseup]

I made a jet removal tool from a scrap piece of water pipe. (it works like a charm)
At a pinch (but please be careful when you try this) you can remove the jets by using a pair of needle nose pliers. A bit fiddly but you can do it.

Once the jets are out, you can then shape one end of your scrap water pipe to fit over the end of the jet. What you're trying to acheive is a square shape at the end of the pipe. I then bent the pipe to a rough 90 degree to act as a handle.

Alternatively you could look for a household radiator bleed tool. There are some pics of these somewhere on the main SOS site i think under the FAQ section.

Although if you have already mostly dismantled your carb to the point where you can see through both the jets whilst still in place within the carb body, why would you need to remove them?
Oyster i think has hit the nail on the head. Partially blocked fuel lines can often be the culprit. Dont forget to clean out the small filter inside the banjo bolt either. (another place where these carbs get blocked up)
In a nutshell the entire fuel sytem must be as clean as possible from the tank to the carb and everything in between including the small gauze filters.

As a rough guidline, compression values for a typical 102 go around 50-60 psi. You will need a compression gague to measure this to see how much your motor has to begin with. Forget that for now, just concentrate on getting the fuel side as clean as you can before you go pointing the finger of blame at anything else.

If you need further help just ask. Always happy to help

Jon

[Eugrasse]

I've cleaned the jets and filter, also the original fuel tap arrived, but it doesn't match with my fuel line connector, the fuel tap is 11 mm male and the fuel line has got 13 mm female connector. Any suggestion? Is the original fuel line 13 mm (1/2 inch) at the carburetor link and 11 mm at the fuel tap link?

[Oyster 49]

Unfortunately you need to forget the metric sizes on seagull engines. The threads are BSF or BSP on the fuel tubes, apart from the odd exception, the spark plug. The 102 fuel tap is BSP. I'm away on holiday and can't remember the Size 1/4 BSP sounds familiar for fuel tube to fuel tap, I can't remember, to much Caribbean rum (on holiday)

Sounds like somebody has fitted odd sized fuel tap and pipe to your engine. we all like pictures by the way.

[headdownarseup]

Yep
Have a go at getting some pics on here so we can see what the problem is.

Oyster's right, we REALLY like pics on here. (we're a strange lot aren't we?)


Jon

[Eugrasse]

For me it's enough to know if you remember if the original fuel line has got a connector to tap smaller than to the carb one, because mine which have been modify has got the same size on both sides.

[Eugrasse]

For me it's enough to know if you remember if the original fuel line has got a connector to tap smaller than to the carb one, because mine which have been modify has got the same size on both sides.

[Charles uk]

What does it say on the propeller hub?

[Eugrasse]

What does it say on the propeller hub?

sorry I don't understand the meaning

[Oyster 49]

You need to make sure you have the correct prop fitted, they are usually stamped, to show what engine they are for. If you have a prop designed for a different gearbox, then your engine may not have the power to drive it.

So firstly check your fuel system, in particularly the fuel pipe. I had exactly this problem on a 102 before, the pipe was clogged with oily sludge and fuel flow at higher power was limited. Leve the pipe soaking in paraffin and blow it through after a few hours, see what comes out of the pipe. Also clean the filter and inside of the tank using paraffin and then soaking in a caustic solution.

I find WD40 sprayed from the thin tube supplied directly into the carb jets works well.

[Eugrasse]

Finally I got pictures, here is my actual set up which has got a not original fuel tap, than I purchased in UK a used original fuel tap which doesn't match the fuel line connector.