32mm carbs in place of 28mm carbs

[mflan77]

I have this 86 suzuki 150supersix that has stock 28mm mikuni carbs I was wondering if I could get a set of 87 supersix carbs 32mm to work. The reason for the swap is that I can not find another set of 86 carbs. Any info on where to find a set of 86 150s cabs or how to do the swap would be great.

 

[mflan77]

Re: 32mm carbs in place of 28mm carbs

Has anyone tried this swap before. Did it work? Do I need to change the jets or advance timing? anyone know? I have been searching for a #3 carb everyday and can not find one. So this might be my only option if it can be done

 

[rodbolt]

Re: 32mm carbs in place of 28mm carbs

beats me, however Fridays marine in Saluda VA may have some used stuff about.

 

[hopalong]

Re: 32mm carbs in place of 28mm carbs

Here are these 94 carbs on ebay again, about 6 hours remain http://cgi.ebay.com/ebaymotors/SUZU...ryZ50439QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

I dont know, But my 86 DT115 carbs worked on my DT140 motor using the 86 intake with the 86 carbs. Did not change anything other than that. Basicly the engines are the same except for the carbs/intake bore size for carbs.

I would guess that increasing carb sizes on an auto engine is a usual thing to get maore horsepower so on an outboard I would assume the same applies. However on an outboard the oil is injected into the cyl whereas on an auto engine it is not. So would an oil injection adjustment be required to run larger carbs?
I go here at times for info about outboard racing and some info on modified bolt ons for outboards
http://www.boatracingfacts.com/forums/forumdisplay.php?f=33

 

[mflan77]

Re: 32mm carbs in place of 28mm carbs

Thanks hopalong my folks live up the street from the (boat recyclers)that is who is selling the carbs. I have talked to a lot mechanics and only one could tell me that he thinks it should work fine. The difference between the carbs is that those carbs have bigger venturies and smaller jets and nossels the epa made suzi do it. Another diff. in the motors is that after 1986 they loosend up the motor for a 5 hr break-in instead of 10hrs. So with the 86 i am sure that it is loosened after the 20 + years of use. Maybee these carbs will work like a good tune-up we will see .I am waiting for them to get here. I will let every one know how they worked

 

[hankll]

Re: 32mm carbs in place of 28mm carbs

I have an 87 DT150 SS, my mechanic told me that 175 and 200 carbs are only difference to the horsepower of the the 150, other than possibly a different adjustment on oil pump. In fact I was told I could actually move the throttle stop on my carbs and actually increase venturi flappers to open up more and thus add more horsepower. I haven't done that. Just seemed like I was asking for trouble, and in fact, members on this forum advised against it, too.
The only thing that would happen as far as I would think is that you'd end up with more horsepower. In other words 28mm vs. 32mm should be more horses. So unless linkages are different it should be fine.

I'm no expert, however.

 

[mflan77]

Re: 32mm carbs in place of 28mm carbs

Hankll, The oil is set to deliver 100:1 for choke and then goes to 50:1 after the choke. Nomatter how much fuel is going through it will deliver that much oil there is no adjustment SO I HAVE BEEN TOLD by two mechanics. The difference in the motrs is in fact in the jets and nossels. The venturi size allowes more air/fuel mixture to go through the carb hints why they changed the jets and nossels to smaller ones when they made the venturi size larger (1987-1994) in '86 the venturi was 28mm and the jets and nossels were bigger and that set-up was not as efficent.


Also the 175 and 200 just ran bigger jets and nossels with a difference in timing / they were advanced more

My first ? was what jets and nossels I would want to use with the new style carbs. if any change would be needed

My motor hase 110 -115 compression that indecates that it is worn or as I would like to say loosened up but that should be what I want with the 32mm carbs and the jets they used for the 150.

I was realy looking for some one who might have moded some outboards before , carbs, reeds, exaust,diflectors ,ect. though it is an intresting topic it could realy help people with the 1986 year models

 

[hankll]

Re: 32mm carbs in place of 28mm carbs

Mflan77, since I'm not real good with 2 cycle engines and also going on what a mechanic said, I was offering hear say info only. Sounds like you know more than I do about the carbs on the 150 block. I was also told by my mechanic that the mere fact that the super six had 2 spark plugs per cyl made it really have a little more horsepower response in the hole shot i.e., better low end torque is what I understood it to mean. not necessarily more horsepower than the same engine with only one spark plug, and also not as much chance of spark plugs fouling. But the info you need regarding tuning the engine seems likely to work with those carbs based on what I've been told about my motor and the ability to tune the carbs and spark response. It did seem a bit of a chore though from the way they described the process to me. I had better throttle response after I gapped all the plugs to .28 than the gap they came out of the box, which I believe was .24, so hotter spark across wider gap helped me not have fouling so easily.

 

[mflan77]

Re: 32mm carbs in place of 28mm carbs

I am fairly new to two cycle engines also. The only reason I can talk about the 150,175 ,200 is that is what I have and I have been doing a lot of researching. I also met an old suzuki mechanic that has worked on suzuki's since 1978 but he still could not tell me about the swap. He said that suzuki tunes their motors so tight the smallest change could make it not run well at all so when we started looking at the carbs he thought I should wait until he could get a solid answer on what the real diff. was.


I also found out that they changed the water jacket design so 1986 head gaskets will not work on a 1987.

Maybee the water jackets were changed to help with cooling when they started to run the motor a little leaner.

Anyway I did buy a set of 1994 carbs and as soon as they get here we will know how it all works

I am one of those people who cant help themself seem like I am allways getting into a new project. I traded my 1967 chevy c10 with a built 283 I mean it was built ! for this 19' bass boat with the 150ss on it the motor seemed to be ok on the muffs but when I droped it in the water it was junk And so now I get to learn about outboards but thats ok I am pretty good with mechanical work maybee next I will try a rotory engine that what my RX8 has in it and they are quite intresting.

Thanks for all your guys help I do get to learn a lot from these forums

 

[mflan77]

Re: 32mm carbs in place of 28mm carbs

Ok, I got the 94' carbs and they are actually 24mm venturies. So i did some other calling around and they used all three sizes in the 150 24mm, 28mm, 32mm . Anyway got them on and at first it ran great - good idle ,good rev so I went to the dock. It was hard to start 2-3 times before starting I put it in gear and it stalled the batt. was dead so I took it back home. The next day I went to start it and it started right up but idled ruff and when I throttled it would rev but with a miss or cough when rpms hit 3500 it acted like it had a rev limiter - like on my car. What could cause this ?

 

[hopalong]

Re: 32mm carbs in place of 28mm carbs

When you started it the next day did you have it in the water or on muffs. Most all Suzukis from the 86 on have a rev limiter. For your motor I dont know what rpm the rev limiter is set at to reduce the rpms at but once reduced youre in the neighborhood of 3500 rpms.
Did you check over the 94 carbs internal settings looking at the fall of the needles and floats. And did you clean them or just installed them out of the box? What do the plugs look like after running the motor? is there gas in the chambers. If you choke it a bit will the motor run better?

 

[mflan77]

Re: 32mm carbs in place of 28mm carbs

1. I took the bowls off the carbs everything looked good they even lokked like they had been cleaned w/ I did notice is that one of the pilot jets 77.5 was missing so I replaced all the pilot jets with the one from my carbs they are 80 insted
( remember the day before it ran great other than the stall on engage and no batt. to restart but in a tank it ran great )

2. The plugs are wet but one cylinder is wetter than the rest / New plugs would help to tell better thats next week - the boat is at my friends house an hour away



3. Some of the wires from the coil packs are cracked with tape on them


4. I did pump the bulb that made no diff. / I did not ckoke it


5. My carb gaskets are old and ruff and 1 had a tear on the edge so I used them only the black gaskets with black rtv sealent the green ones I put back on cause they looked good

So do you think I might need to change plugs - replace coils that have cracked wires - and get new carb gaskets.

Can I get just the carb gaskets that I need and the coils dont sound cheap

 

[hopalong]

Re: 32mm carbs in place of 28mm carbs

2. spark plugs are wet with gas or oil?

3. Well, I guess you would know if you have "cracks" in the plug wires that you most likley have ignition wire/leakege/breaking down. I have remedied such a problem years ago using auto engine plug wires. I cut the wire about an inch from the coil end and installED an MSD male end onto the end of the wire and then using a "new" spark plug wire setup with fm end to that end and the typical spark plug end at the spark plug.
Otherwise you would need the entire coil/spark plug wire assy. I've seen them on ebay sometimes along with the entire CDI unit. Have you tried using an insulated plier holder(totaly a plastic type plier), like an electrician uses to pull fuses out of high volatage lines and attach a steel rod or screwdriver to the insulated pliers and run up and down the cracked wire and to the engine ground to see if there spark is jumping to ground from the wire. It would be more noticeable at night or low lighted levels. If it is jumping to ground usually it would kill the engine or have a definete affect to the rpms.
5. Carb gaskets to intake should be available through Brownspoint or go to NAPA and get the same type of gasket material and cut/make your own

And yes change the plugs, its cheap and you'll know that the plugs can be eliminated from the troublshooting issue.

And as stated above the coils sometimes shows up on ebay. BTW the coils may be the same as some other OB models...look at the illustrated parts/no. at Brownspoint.

But think about this if your ignition issue turns out to be ok then I would look into the operation and rebuild of the 94 carbs themselves. Also wondering if you could use only the 24mm carbs in place of the one/s you had a broken needle and use your original ones on the other intakes?

 

[mflan77]

Re: 32mm carbs in place of 28mm carbs

Hopalong, it seems like I should use all 3 insted of 2 -28mm and 1 -24mm so all carbs are producing the same results

I do like the sound of the plug wire fix you offered - " thats ingenious " it funny how we don't think of things ourselfs sometimes.

Would'nt there be burn marks where the wires are grounging ?

I did buy gasket materials but was to lazy to use it. Thought I woul try the black rtv. I'm kind of a do-do

Here is what I think tell what you guys think
1 change plugs
2 replace carb gaskets
3 do wire fix hopalong mentioned


Did another compression check today just to double check and it was as follows 108-110-111-110-109-110 like I said lose but not to lose

If I can't get it this weekend I will just repower with a 91' evinrude 88spl that I am getting ready to finish hate to do it but I want on the water and that will give me time to figure this one out

Thanks again everyone