Jetting 2.7 looper with midbores?

[callyer]

Anyone have the stock jet sizes handy? 1986 2.7 looper, I just installed a set of midbores and would like the stock sizes to work from.

Thanks,
Craig

[racer]

What year mid bores? guts in or out of air box?

[callyer]

Guts out, and they are from an 89 johnson 225.

[callyer]

The numbers off the carb bodies is 395039, hopefully they are the midbores, but if they are the small, I really don't care, i just need to get it jetted appropriately.

thanks,
Craig

[racer]

89 225 came with .034 idle, .047 mid, and .062 main these are with guts in the air box, I would increase 5 and 6 to .064 with guts are 1-4 with 74d main and .076d on 5 and 6

[callyer]

No other changes based on the fact that I have the 2.7, because the 89 was a 3.0 right?
Thanks for your help!





89 225 came with .034 idle, .047 mid, and .062 main these are with guts in the air box, I would increase 5 and 6 to .064 with guts are 1-4 with 74d main and .076d on 5 and 6

[callyer]

Alright, got a couple questions, one, I am pretty sure these are mid bores (from an 89 johnson 225 supposedly) but could someone verify the numbers for me because they look SO small compared to my old big bores the carb body numbers are 395039.
I am also a little confused b/c I had to change the "stagger" on the carbs/ throttle bodys (mine has the drivers side bank lower than the other side, so I switched around the top arm to make it right) Just looking for a "that is normal" from someone.

My BIG concern at this point is I have lost the original diagram I made to tell me the hose routing, and I have removed all fuel lines around the carbs, and the re-circ (vacuum hose looking things) lines as well, so if anyone could describe or send a diagram/ or pictures that would be great!!!

Here's the starting point I have for jets, from what Racer said I am going to go with 74D mains and 76D in the bottom two cylinders.
42's in the mids (richer than stock, was going to start with 40's but I have the 42's already)
And I have a set of 34's on order for the idle.

As always any wonderful input/ suggestions/ information is welcome!!

Thanks Guys!

Craig

[lokinutz]

I have a factory service manual that has excellent diagrams of all the hose routings you can borrow if you'd like. I work at Thomas/I-17 all day tomorrow if you would like to pick it up. Be there for all 24 hours of the day. More than happy to take a look at what you have if you want to stop by.
You shouldn't have needed to swap linkage around.
I also have a set of small and medium bores handy if you'd like to see those in person too.

[callyer]

Thanks! I could def use the info and a second set oif eyes!! Unfortunately I am off today, but work all weekend!! (Crappy) will try to take a look at where my inspections are and see if I will be around there at all!!

Thanks!

[lokinutz]

Sounds good. I will throw the stuff in my truck just in case. Also work on Tues and Fri next week. You still have my number?

[callyer]

Sorry for delay, I have been workin non-stop, gonna try to start her up today, 34c's still not in, gonna try some jets I have that are drilled to slightly smaller. One thing I still don't know is the small vaccum looking hose routing, is it fine as long as they are all connected? Or is there a specific route/flow, I think I have them ok, but would like to know for sure. I will try to get w lokin on this, but I am running short on time today. Thanks for all your help guys, it is appreciated.

[Captain75]

89 225 came with .034 idle, .047 mid, and .062 main these are with guts in the air box, I would increase 5 and 6 to .064 with guts are 1-4 with 74d main and .076d on 5 and 6
Hello!
I know this is an old thread, but I have been tryin to figure this out aswell, just to get a crisp throttle response when stabbing the throttle going from idle.
I have two 2.7 motors, one is an -86 and the other an -87. Both motors came to me with midbores, with the same orfices installed, however these motors seems to be jetted like nothing else I have seen on this site... #14 in the mids, which I think is the same as the bigbores? The idle circuit has got #48, needs fast idle lever to start, but idles perfect when running.
There is not so much written on this topic on this site, however I found this thread where the OMC God(racer) had answered! I tried the same orfices as racer stated above, but my motor cant handle #34 in the idle circuit, gets to rich and the motor wants to die on me!? I have installed 65D and 106pullovers, instead of stock 62D, mainly as an insurance due to fingerports and some other mods. Motor runs like a raped ape when on the mains, I just need to get rid of the blubbering going of idle, in order to be able to turn a bigger wheel. I still have the guts in the airbox.
Someone must have dealt with the same problems before, please chime in!

//Anders

[Captain75]

Ttt...

[perfmarine1]

Captain, Keep in mind the fuel you have in Sweden. In the US back in 1987 there was not 10% ethanol in the fuel. So today these motors are all on the lean side with many suffering take off problems and must be jetted up.You need to consider your fuel in Sweden when jetting and not rely on us guys in the US as fuel may be different. Here is a break down on the fuel history used in the US.

http://www.fuel-testers.com/ethanol_fuel_history.html

[Captain75]

Thanks Greg, I'm sure you have an important point.
Been out with the family all day on the lake, tried some orfices, think I'm getting closer to the sweet spot!
The main circuit is good enough, maybe a bit rich, but thats ok! #65D and 106 pullovers.
midrange #48 and idle #40. The throttle response has clearly gotten more crisp, however the motor has trouble idle because of the richness of the mixture. I've tried to adjust timing to give it some more rpms but it doesn't help.

Tomorrow I will lean out the idle again, this motor idles like a singer with #48 orfices, I just afraid that I will be to lean together with the current midrange orfice, and bogg again on takeoff.
Dont know how much the two circuits affect each other...

//Anders