Irvine 46 Questions.

[David Davis]

I have both the Irvine 40 and 46. They are both red engines featuring black carburetters with "Made In England" cast into the crankcase. Does this identify them as Mark IIIs?

 

The 40 sarts and runs well but a mist of fuel escapes from the carburetter. I suspect that the Orings need replacing. Does anyone know a suitable supplier of Orings?

 

I have dismantled the 46 to replace the bearings. The front bearing has seals on both sides. Should I leave the seals in place on the new bearing or shoud I take out the rear seal?

[Denis Watkins]

Try this chap on 

 

[Engine Doctor]

Hi David . Are you sure the fuel escapes from carb ? The usual fault with those was that fuel would be pushed or blown out of the front bearing covering the model and using a lot of fuel. The "0" ring on the carb would not cause any fuel escape, on the contrary any leak there would allow air in causing a weak mixture. Check it again and if the front bearing is the cause change the bearings and fit a sealed type (rubber seals) bearing at the front, just remove the rear seal before fitting.

Edited May 12, 2022 by Engine Doctor

[Martin Harris - Moderator]

I had a red .46 from new which had a loose fitting (rubber sealed) front bearing.  It initially manifested itself by a refusal to stop...it would run for  minute or two with the throttle completely closed...but progressed to spinning in the housing before I realised the cause, which was air leaking past the bearing and its housing.  There was a lot of oil migration past the front bearing and I had assumed it had a shielded rather than sealed bearing which I stripped the engine to change - finding an intact RS version.

 

Refitting with Loctite Bearing Fit located it securely and sealed it perfectly - and it stopped as soon as the throttle was closed.

[Engine Doctor]

On 12/05/2022 at 20:15, Martin Harris - Moderator said:

I had a red .46 from new which had a loose fitting (rubber sealed) front bearing.  It initially manifested itself by a refusal to stop...it would run for  minute or two with the throttle completely closed...but progressed to spinning in the housing before I realised the cause, which was air leaking past the bearing and its housing.  There was a lot of oil migration past the front bearing and I had assumed it had a shielded rather than sealed bearing which I stripped the engine to change - finding an intact RS version.

 

Refitting with Loctite Bearing Fit located it securely and sealed it perfectly - and it stopped as soon as the throttle was closed.

Yes a loose bearing has same effect . I have found them to have shielded and sealed bearings and loose fitting bearings over the years. Bearing fit is a must in any IC enthusiasts armoury.

[Nigel R]

ED would you use bearing fit on ID or OD of the bearing (or both) ?

[Engine Doctor]

You only really need Bearing Fit on the OD / outer case of bearing to stop it turning in its housing , as the alloy housing quickly wears if too loose.  The shaft should be a sliding fit into the ID of the bearing an NO  bearing fit needed. If  the shaft is a very loose fit the either it's the wrong bearing ( possible) or the shaft is knackered ( highly unlikely)

Hope it helps .

Edited May 15, 2022 by Engine Doctor