RPM MAX/sneezing

[sparkroost]

What is the Max RPM these motors(Johnrude v4<br />'s) can run?<br /><br />I was talking to someone who used to race them and was running 8800! <br /><br />Stock reeds will flutter at 6200?<br /><br />I have searched on sneezing here. Seems a lean condition at idle. My motor sneezes EVERY time it seems when starting cold. Runs great. 77 johnson javelin 85hp. 135psi in all cylinders. Plugs are paper bag in color. I wanted to get the boysen reeds, but I am thinking 1 sneeze and I am off to get more reeds.. what can I do?

 

[RKwood]

Re: RPM MAX/sneezing

The installation instructions from Boyseen are a little confusing. They suggest to 1) Decrease the size of the idle air jets, or 2) Do nothing.<br /><br />Believe it or not!

 

[sparkroost]

Re: RPM MAX/sneezing

This motor does not have air jets(I don't think anyway). Only the main jet and the idle jet. I can't see any other jet's/orafices. 2 carbs with 4 jets in each varb body.

 

[RKwood]

Re: RPM MAX/sneezing

I have twin '84 v4 crossflows, and each of my carbs have six jets.<br /><br />High and intermediate fuel jets in the carb bowl, and two more, the idle air jets, above the throttle plates.<br /><br />I'm no expert but I'd have to believe your carbs are simliar.

 

[Dhadley]

Re: RPM MAX/sneezing

Yes the crossflow is capeble of that rpm with modified port timing, among other things. Yes the stock crossflow (not looper) reeds start to flutter around 6200. Yes Boyesen recommends to reduce the idle air jet on carbs that have them. Reducing the size on an air jet richens up that circuit. Yes a "spit" or "sneeze" is about the only thing that will hurt the Boyesen reed.<br /><br />Its not unusual to have to re-jet the idle circuit on motors that old. They were calibrated for fuel of that era. We lost that fuel many years ago. Richen up the idle circuit (if all else is OK like butterflys completely closed) and install the Boyesens after you cure the "sneeze". You will like them.<br /><br />Good luck!

 

[sparkroost]

Re: RPM MAX/sneezing

Good points DH!<br /><br />ok.. the port timing thing has me a little interested... You are referring to exhaust port timing? Needs to be raised to obtain 8800?!?(no I really don't need 8800, just curious). What about the intake ports?(try to be open minded here. I have read tons of posts here and the answer is all the same... don't Screw with it(unless you know what you are doing). The pain in the butt about this is that there are 8 ports pr. clyinder, 4 of which are very deep, the other 4 are much easier to do.<br /><br />I talked to a fella last week and he also told me to stay away from 6200 rpm! Harmonic balance problem there. Above or below is ok, just not the 6200. Said the crank would snap, yikes!<br /><br />Since I work for a machine/forging shop I have the ability to do whatever I wish here at night, as long as I keep the million dollar machines running I have spare time to do "other" things.<br /> I was considering doing some port work to add to the other mods I have added. I have already cleaned up all the casting imperfections, and cut the pistons "excess baggage", and balanced. A little port work would be nice but this work takes a little experience. .020 raise on the exhaust ports would probally add some r's and HP? OR... not worth doing? Or the wrong amount?<br /><br />Oh.. I don't have the air jets on either set of carbs I have.. I have 1 set that are 1 5/16(1973 carbs) and another set of 1 3/8 from a 140. The manual(clymer junk manual) says if I have the 1 3/8 to replace them because they run too lean. This one I can't understand.... too lean.. add bigger fuel jet's/ smaller air jets.. but replace them.. seems foolish.

 

[sparkroost]

Re: RPM MAX/sneezing

1 more thing about 85hp engine. The plugs look great in color after idling. What I notice though is on startup on the water when fishing.. smokes alot at first startup when sitting for say 15 minutes. Normal? <br /><br />I would really like the boysen reeds... BUT.... most motors will run lean at startup due to denser air. If I compensate with a larger fuel jet then when I actually do warm up I will be too rich, right?(not in the high end, but won't that screw with my 800 rpm "troll"?

 

[Dhadley]

Re: RPM MAX/sneezing

I would bore out the cylinders to 3.500 (standard 115/140) and match the 79 140 style porting. The intake ports on an 85 are very small. The 85 exhaust ports are a bit smaller too. Be sure to get a set of 3.5" heads (again - 115/140 style) at that point. Since the block is apart I would add the "bubbled" exhaust plates. Dont worry about the inserts - we discard them anyway.<br /><br />The stock port timing and ignition will work to about 7000 or so. We were also told about the harmonics at 6200 (on V6 c/f's) but never saw it. I'm not saying it's not there - I'm saying we never had a problem with it.<br /><br />Since you are concerned with the trolling deal I would not raise the ports above the 140 height. However I would "square" the ports with a 1/4" end mill. That will help torque. You could scollop the pistons and block but at less than 7200 I would rather have the skirt strength. You could open the bottom end of the intakes (lower them) some also to create more transfer area.<br /><br />The big gain is in the intake manifold area. Get the motor running with whatever changes you decide on now and get it dialed in. When the intake comes back off to do the Boyesens you can do the intake work then. <br /><br />As for the carbs - they will all work. Even the V6 cf's. Keep in mind that the larger the venturi the slightly more top RPM youll have but slower acceleration. Smaller venturi's have more acceleration but slightly less top RPM.<br /><br />Good luck!

 

[sparkroost]

Re: RPM MAX/sneezing

DH, I am referring to the 115 I have, lol. I have been using the 85hp for the past year and a half. That motor is coming off and the 115 is going on. I have wanted the boysen reeds but have read all the posts on snezing. I figured the 115 was going to sneeze as well. Just trying to look ahead a little here.<br /><br />The 115 is 1973. High compression. Added bubble exhaust, cut block. I heard the megaphone is different on 1973 135 vs. 115(read it in posts but don't believe everything I read)??? This would be an important change if the chamber is different. If you happen to know please let me know as I will look for it.<br /><br />I am using the 140 intake. IT's further from the block than the 115 was. Should be an improvment. I have removed all the high casting marks, but not polished it. I don't think that will make any improvment. Question is.. what else can I do to the induction system short of buying huge velocity stacks?<br /><br />As for porting.. the 140's had 3 transfer ports pr. side.. how can I match the 140 style if I have 4 ports! <br /><br />Would you say to open the exhaust AND intake ports the same? I am not going to go crazy with the porting. I have had input already to square the ports. If I can get away with squaring the exhaust only, I would rather do that. If I need to do both I will do that as well. What I DON'T want to do is open the exhaust to the point that I lose too much intake charge as the exhaust expells. This would make the motor inefficient.<br /><br />Another thing I was looking into is the exhaust area. In the block there are castings to drill and tap for the exhaust tuner. These "stubs" stick up and look like they will prohibit exhaust flow. There is also 2 webbing(looks like block strengthining) castings near the bottom of the block. These look like they will also reduce exhaust flow. Can these be removed without any ill effects?<br /><br />As for the skirts, I will not touch them at this point. I got some good advice on what to do with them, but I am going to leave that alone.<br /><br />Sorry I ask too many questions. I need to gather as much input on porting as I can, so I get it right the first time as this is the most crutial "make or break" point.<br /><br />Thanks for all the information you have given!

 

[Dhadley]

Re: RPM MAX/sneezing

Dont worry about the little bosses in the exhaust or the webbing. Youll get plenty of flow. Polishing the intake will do very little at best and may hurt at the RPM youre talking about. Just square the ports and youre good to go. The stock unsquared ports will go 7000 or slightly more. <br /><br />The pistons you have are for the 1973 then? They are different than anything else.<br /><br />Sounds like you are ready for assembly or close to it. Get it running and broke in and we'll tackle the reeds and intake. Dont worry about stacks or cutting the hood open!<br /><br />What kind of boat? I hope it has a pad to take advantage of all your work!<br /><br />Good luck!

 

[sparkroost]

Re: RPM MAX/sneezing

yup, got the weisco pistons for that year. I was in luck.. they just started making them.. for some reason.<br /><br />My boat.. I am almost ashamed to admit what I have now. 17' wellcraft fisherman. V-hull in front, flat in the rear, high flat sides in front to knock the splash down. I do alot of fishing in the bay area, near galveston. Was a project boat I bought last year next to nothing. I have been spending money on it ever since. My way of getting a new/old boat. I would actually like to find another boat that will take some chop in these waters. I am already having to beef up the transom in this one. Would like to find a good boat that will last and hold some value. 18' I think might be better, but something that does not need a 200hp motor. 120 or so HP rating. I am a complete moron when it comes to boats. I just have not researched enough to make good decisions on a boat. I love to fish here in Galveston and that is the primary purpose of the boat I am looking for. But when I want to get somewhere.. I want to get there FASSSSTTTT, if possible.

 

[Dhadley]

Re: RPM MAX/sneezing

Wellcraft's a good boat. The bottom isn't very responsive to small changes in torque but itll certianly be better than the 85. One thing we may want to look at is a jackplate. By moving the motor back 6" you move the center of gravity, or fulcrum point, back which helps lift the nose.<br /><br />Just keep you eye peeled for a boat you like with a pad bottom (looks like a ski on the hull - sort of). Most have a step or notched cutout also. The pad bottomhulls respond very well to even small torque increases. Most flats boats are like that as well as most bass boats. <br /><br />Keep us informed. Good luck!

 

[sparkroost]

Re: RPM MAX/sneezing

funny you mention the jack plate... I was going to ask about that in the last post but was gettin glong winded as it was. I do have a jack plate on this boat. The only problem I am having is it is making the transom flex a bit more. I was going to ask if it was better to have it, or just discard it. I think it has a total travel of 6", maybe a little more. Made by "jack-plate"?. I think I spelled it right. Says that on the side anyway, molded into the aluminum. It's a very nice piece.<br /><br />Yes.. the 85 is not enough for this boat. Big diffrence than the 115, especially outta the hole. Takes longer to plane and does not have near the speed.<br /><br />I am confused about the pad bottom. I was thinking you meant "flat" in the rear, but I think I am lost. It's not flat at the rear of the boat. Has a little V to it, but not much. Actually I think it steps at the rear. Maybe 2 or 3 steps to the final bottom.<br /><br />I really want to thank you for your inputs. I am sure there are others lurking on this one Hope I didn't sound to "green" with my questions. Always learning!

 

[Dhadley]

Re: RPM MAX/sneezing

We're all learning.<br /><br />Your boat does not have a pad nor a step. The long flat areas you are looking at are lifting strakes. A pad will look as if the bottom has a ski on it. A flat surface right in the center anywhere from 4 1/2" to maybe 8" or so wide. Once you see one you will understand right away.<br /><br />I'm very concerned about the transom flexing. A V4 on a 17' boat should not make the transom flex even if its on a 15" setback. Besides the obvious its hurting your trim range. Probably only slightly but it means the transom needs attention.<br /><br />I would suggest that before proceeding you get it looked at and repaired or at least reinforced. I've had V8's on a 6" jackplate bolted to a 19' boat that never moved the transom.<br /><br />Better safe than sorry!

 

[sparkroost]

Re: RPM MAX/sneezing

welp.... I was afraid of that.. The transom has already been re-inforced. But half-a$$ed. Someone took a aluminum plate and bolted it to the transom. The plate covers both sides of the transom, but on the inside of the boat it only goes down to the splash well. The aluminum has bent outwards away from the boat. What I am seeing flexing is where the livewells at the back of the boat meet the transom. It's cracked there. When I am on the lake and pushing her I can see it flex. It has been bothering me lately. I never noticed it before. The pain about this is there is a deck in this boat. so in order to get to the transom bottom I would have to cut out the deck in the rear and re-attach.<br /> <br />I am thinking that I might just need to get a new boat with a blown motor, or a new boat without a motor. Fix it? or get another? (I was not too smart at buying this boat)

 

[sparkroost]

Re: RPM MAX/sneezing

After reading the many posts on transom's I am convinced that I am in need of replacment. Time to stop fooling myself and bite the bullet. <br /><br />boston whaler. STUPID me passed up a deal on one from a relative. !@#$!#$%!#%!#%!#$ $7500, clean. (kicking myself).<br /><br />Someone out there have a boat with a rotton motor?<br /><br />The thought of fiberglass dust is making me gag.