Snowblower Forum banner
1 - 10 of 10 Posts

·
Registered
Joined
·
70 Posts
Discussion Starter · #1 ·
I havent gotten to pull my 28 sho carb apart yet, but wondering if anyone has stock jet sizes for these engines?

I am assuming the jet will be numbered, but I have seen plenty without numbers on other carbs...thus--searching for the correct baseline jet number ax306 engine.

thanks.

I did search through threads.......no answer yet...
 

·
Registered
Joined
·
1,182 Posts
I havent gotten to pull my 28 sho carb apart yet, but wondering if anyone has stock jet sizes for these engines?

I am assuming the jet will be numbered, but I have seen plenty without numbers on other carbs...thus--searching for the correct baseline jet number ax306 engine.

thanks.

I did search through threads.......no answer yet...
As @1132le said his main jet was numbered 114 while mine was un-numbered. The jet that fits is a Honda (I used the one from the GX390). The Honda Clone jets may also fit. I tried to get a jet from a local Honda dealer but I needed machine details and not just the jet size. I got the jets online using the latest model GX390 for the identification numbers, only a few $'s each and shipping to Canada is not expensive.

To get an idea of size i forced a tooth pick into the jet at its venturi. Then did the same to a 115 Honda jet, and the narrowed tooth pick is much the same size within my measuring capabilities with a digital vernier calipers. I don't have the numbered drills that can size the jet but the lists of those drills gives the diameter in mm and inches. The 115 jet has a diameter of 1.15mm so you can get the inch specific diameter from the drill size listing. The Honda experts here warned me about drilling the main jet to the size you want since it would reduce or eliminate the venturi effect. As a result the flow changes and is not as effective.

I chose a 118 main jet which is slightly larger than stock 114 main jet. No snow to try it out yet and nothing much in the forecast. I did try the engine in early and late fall. At 15 C ambient temp my engine started easily in the usual way (3 primes, full choke and throttle and one pull of starter) it ran at 3,900 rpm and no sign of black smoke. At 3 C ambient temp my engine started the same way and ran the same. I don't know yet how it will run under load but at least it runs the impeller and augers and drives through the gears without any drop in rpm (on-board tach).

Good luck with your project.
 

·
Registered
Joined
·
70 Posts
Discussion Starter · #4 ·
thanks to both of you..

if its close to a Honda gx270---should be 88 range...and I have spare jets from 92- up from other hondas and some new assortments. I am hoping its numbered....otherwise ill be blind.
drilling jets is a no no---def not same flow characteristics. Heard all about that in the drag racing world.

anyways, still looking for the oem jet on a ax306
 

·
Registered
Joined
·
70 Posts
Discussion Starter · #5 · (Edited)
Ok, I got off my butt..... the jet is a little rough an stamping Not clear.

looks like a 102. larger than expected. interesting. thats larger than many older gx390s...and pretty close to the latest gx390 i checked at 105.

i might go to a 105----0.41 ...just cause I can....LOL


Natural material Body jewelry Jewellery Art Wood
Body jewelry Human body Amber Wood Jewellery
Jewellery Gas Body jewelry Metal Wood
 

·
Registered
Joined
·
70 Posts
Discussion Starter · #6 ·
SO....i just put a 41 jet in it...1 size bigger--if a 102 is a 40.

lost 100 rpm. now 3740.....was 3850 with stock jet.

there was no lean misfire with either jets.

im going to roll with it for now.....see how it acts in cold with snow....around 45f today so it could change in 25f temp....

I was expecting 92---95....surprised it came with a 102.
 

·
Registered
Joined
·
1,387 Posts
SO....i just put a 41 jet in it...1 size bigger--if a 102 is a 40.

lost 100 rpm. now 3740.....was 3850 with stock jet.

there was no lean misfire with either jets.

im going to roll with it for now.....see how it acts in cold with snow....around 45f today so it could change in 25f temp....

I was expecting 92---95....surprised it came with a 102.
iam pretty sure the numbers on the jets dont mean the same thing between clones and honda and lct ive seen it on jet sheets
shhould not have lost rpm=== something is not right
 

·
Registered
Joined
·
70 Posts
Discussion Starter · #8 ·
iam pretty sure the numbers on the jets dont mean the same thing between cones and honda
shhould not have lost rpm=== something is not right
if it went rich.....it will lose rpm.

well, I have nothing else to judge, except that stamping of 102. I wish there was a spec somewhere....thus my search.

i can put the stock one back in.....102 in a 306 is fairly big for stock.
 

·
Registered
Joined
·
1,182 Posts
There have been several posts in the Honda forum about updates that Honda has made to the stock jets on several models. I think the GX390 is now up to 110 or so. @tabora has the latest spec in answer to questions and in his thread dealing with Honda info.

I have found with the same jet my engine speed will be slower when cold, but increases engine speed to nominal governor setting after it warms up a bit. The new larger jet is behaving similarly. At full operating temperature in deeper snow the stock jet engine will run at 3,950 rpm. I wouldn't change the jet until you have run the machine up to full operating temperature after quite a while of operating conditions and if the performance suffers.
 
1 - 10 of 10 Posts
Top