625 to 630 p/c intake differences

[imanoob]

I have what appears to be an 84 jonsered 625, when i got it it was showing over 160# compression. I pulled the jug off to inspect it and it had one small score in it, needless to say everything else is there and now i have a 630 dual ring piston and cylinder for it. It appears the 630 jug is a bolt on type, and my 625 had a boot that clamped on. I cant seem to figure out how to make it work with the carb from the 625. is there something i am missing or is there a trick to this? I tried searching but mostly came up with 630 to 670 conversions.

I can get pictures if needed, thanks for any and all help!

 

[weimedog]

I can get pictures if needed, thanks for any and all help!

Send pics..I've just swapped out a 266 jug for a 272 on the last project of that type, significance is the intakes were radically different. The good news was I was able to "retro" the later 272 intake manifold into the place the old 266 system was on the 266 cases, using the same rubber grommet/damn that came with the 266. BTW there would be NO way to retro the 272 system to the 266 jug as the entire casting and machining was different from one to the next. Relevance? You pretty much have to use what ever intake manifold setup that was designed for the particular jug you want to use ..with that jug. So you need to find an intake manifold from a 630 to make that work is my guess...

 

[almondgt]

You will need an Intake from a husqvarna 266 or a jonsered 630 intake obviously for your jonsered 630 cylinder. You will need 2 intake mounting bolts and 2 carb mounting bolts. You will need the correct intake gaskets. You will need a jonsered 630 carb or drill the Jonsered 625 carb you have so the impulse will work. You also have to remove the top cover off of the Jonsered 625 carb and replace it with a flat top off another tillotson carb that fits. The sealing collar that goes around the intake maybe different too depending on the year of your crankcase, not sure. You can check the ipl for jonsered 630 and Husqvarna 266 ipl and go from there
https://docs.google.com/viewer?a=v&...wD0aUu&sig=AHIEtbR4O7-0qMlB3VnQXYcQkQAz-L4H9A

https://docs.google.com/viewer?a=v&...MQhj4s&sig=AHIEtbQfdCFTbu6cVR36mTBsjqywvTKFag

 

[imanoob]

View attachment 216900
View attachment 216901
View attachment 216902


The 630 jug is the one with the plastic intake. It also appears to not have an impulse fitting (i think thats what it is), the 630 mustve had the fitting in the case? There is no way the 625 boot will fit on that plastic piece because its too big around and too long.

 

[weimedog]

(BTW,,I have that setup from the 266 cylinder I took of the last project saw.)

 

[SawTroll]

A 1984 625 sounds odd to me? :msp_confused:

 

[imanoob]

(BTW,,I have that setup from the 266 cylinder I took of the last project saw.)

what exactly do you have? I think what i need is the piece between the intake and carb and the 2 carb bolts. I already have the intake piece that goes on the cylinder and the bolts and gasket for that(shown in pic).



Almondgt- what is the difference between the 2 carburetor tops? And how would i go about drilling out the carb for the impulse? It would seem to be easier to just get a 630 carb and put that in.

Thanks again for the help guys. Im trying to get this saw together so i can sell it to fund my 2 272xp's and 394xp

 

[imanoob]

A 1984 625 sounds odd to me? :msp_confused:

maybe it isn't, 8450540 is the serial number on the tag. I thought the first 2 numbers were year but could be wrong :help:

 

[almondgt]

Jonsered 630 carb on the left, jonsered 670/625 on the right. The 625 impulse works through the top of the carb with the hose connecting it to the cylinder. Boring the carb can be risky/ tricky but can be done...The impulse hole should already be started in the throttle end of the carb (top right ..1:00... looking at the throttle plate), so you can use this as a guide. You have to drill in until you hit the verticle shaft that would be directly under the impulse pickup on the 670 carb top. The tillotson flat carb tops should swap out from a husqvarna 61, 266, 268 272.

 

[imanoob]

Jonsered 630 carb on the left, jonsered 670/625 on the right. The 625 impulse works through the top of the carb with the hose connecting it to the cylinder. Boring the carb can be risky/ tricky but can be done...The impulse hole should already be started in the throttle end of the carb (top right ..1:00... looking at the throttle plate), so you can use this as a guide. You have to drill in until you hit the verticle shaft that would be directly under the impulse pickup on the 670 carb top.

Ok, and as far as the tops go what i need to do is get rid of the one with the 90 degree fitting for the impulse line, correct? Would it have the same effect if i closed the hole or would it be better to get the right top for it?

edit: if the 272 tops fit then i should have 2 of them laying around!

 

[almondgt]

You need to drill the 625 carb for sure. If you can close the top it should work.

 

[SawTroll]

maybe it isn't, 8450540 is the serial number on the tag. I thought the first 2 numbers were year but could be wrong :help:

That is only the case with saws made from some time in 1999, and later. The system has changed several times, and this saw was made 1988, week 45.

 

[imanoob]

You need to drill the 625 carb for sure. If you can close the top it should work.

Ok i found the top off the 272 and it does fit. The hole i need to drill has been started, but im not exactly sure on how far i have to drill in. I really dont want to mess this carb up if i can help it. Will it help me to see if i take the top and the gasket off the carburetor? or, how would i know when i get to the verticle shaft?

And by drilling this hole out it is going to completely bypass the impulse setup right? I just want to make sure, like i said i dont wanna mess this carb up

thanks!

 

[almondgt]

You have to remove the top and gasket to see how far to drill in. Just drill in to the inner most vertical shaft
Yes, drilling will bypass the original impulse from the top of the carb to the cylinder head

 

[Cantdog]

One other thing you will want to check is the size of the bore in the manifold...there were 2 different sizes used on the 630...the small one matches the 218A carb large one matches the 225 and other later carbs. I'm guessing the you would have the smaller carb on the 625..just would be nice if the carb and manifold bores matched.

 

[almondgt]

One other thing you will want to check is the size of the bore in the manifold...there were 2 different sizes used on the 630...the small one matches the 218A carb large one matches the 225 and other later carbs. I'm guessing the you would have the smaller carb on the 625..just would be nice if the carb and manifold bores matched.

This is where experience comes into play. I did not consider the manifold size compared to the carb size. Cantdog is the member who taught me how to drill the carb and successfully get my Jonsered 670 converted to a 268xp. I may have not said then, but I say now Thank you Cantdog for your advice:msp_thumbup:. almondgt

 

[Cantdog]

This is where experience comes into play. I did not consider the manifold size compared to the carb size. Cantdog is the member who taught me how to drill the carb and successfully get my Jonsered 670 converted to a 268xp. I may have not said then, but I say now Thank you Cantdog for your advice:msp_thumbup:. almondgt

LOL!! You are very welcome almondgt...actually, I too, am merely passing on information that I have picked up along the way and that others have taught me as well. This is a very fun and diverse family of saws to work in. With splendid results..I might add. BTW I never heard how do you like your Gillardoni powered "678"????

 

[almondgt]

Thank you for asking about the jonsky 678. The top end I installed is a nos Mahle 50zn14. The cylinder I removed from the Jonsered 670 is a Gilardoni. I started the saw up and that is as far as I can take it at the moment. I want to run it spring time to get a better carb adjustment......and it is presently pretty cold outside to monkey around.

 

[Cantdog]

I am sorry ...I think, perhaps, I have merged two different build threads.?? But yes the Mahle closed port 268XP cyl is super....the first one I built and ported is exceptionally strong but only turns about 800rpm over stock but doesn't slown down in the cut hardly at all which makes it actually cut quite fast...I am building another in RED this time and plan to raise the ex port a few thousnths to bring the rpm up slightly with out reducing torque....hopefully!! LOL!! Hope your tunes in nice!!