sUZUKI MOTOR

[pmassey31545]

I JUST BOUGHT AN OLDER SUZUKI MOTOR. 85 HORSE. BY OLDER I MEAN MID 80'S BUT I'M NOT SURE OF THE YEAR. MY PROBLEM IS THIS-I HAD A 50 HORSE YAMAHA ON THE BOAT AND WANTED MORE SPEED AND POWER FOR SKIING. THE SUZUKI IS ONLY A FEW, 4-5 MPH FASTER THAN THE YAMAHA. THE SUZUKI DOES NOT COME OUT OF THE HOLE WELL AND DOES NOT TACH UP WHEN AT FULL THROTTLE. BUT IF IT'S IN NUETRAL, AND YOU MANUALLY REV IT IT DOES FINE. SOMETIMES WHEN YOU GIVE IT GAS IT JUST BOGGS DOWN AND QUITS. ANY SUGGESTIONS? ALSO NEED TO FIND OUT WHAT YEAR THE MOTOR IS. aNY HELP IS APPRECIATED.

 

[jafa]

Re: sUZUKI MOTOR

OK , first thing , CAPS = SHOUTING , a serial number , usually on the transom mount would give us the year and model. Bogging down and quitting is usualy associated with varnish or other rubbish in the carbs or, occasionally, one of the cylinders not firing. Dont rev it over 2k on muffs , most 2S motors dont take to high revs and no-loads. What revs are you getting at the moment at full throttle on the lake with average load. You'd also be wise to get a manual as a carb strip down will usually involve a link and synch proceedure to set them up correctly.

 

[pmassey31545]

Re: sUZUKI MOTOR

Sorry bout the caps. I don't have a tachometer so I can't tell you how high it is getting. All I know is when it is idling in the water, it tachs great. When I try to take off it is slow out of the hole and the rpm's arent nearly as high. This is just from hearing the motor run. I will get the S.N. before this evening. Thanks...

 

[bossee]

Re: sUZUKI MOTOR

Hi,<br />I suggest You get a "Tiny tach", does not cost much (check out tinytach.com ).<br />You really want to get optimal RPM at WOT (Wide Open Throttle).<br />Or try to find a second hand Suzuki tachometer.<br />Without a tach You have no idea if you are running at manufacturer recommended RPM range (under rev at WOT is like running uphill on 5 gear in a car, over rev will cause the over rev limiter to kick in, hopefully).<br /><br />Make sure the throttle is wide open when the control box lever is max forward.<br /><br />Suggestion:<br />If the service status of Your Suzuki DT85 is unknown You should consider change to a new impeller (there is a impeller kit with all You need), a carb kit, and probably a new fuel (rubber diaphram set) pump. Also make sure the fuel bulb stay hard after you have squeezed it. You may want to check the thermostat(s?) also so they are in good shape and open at specified temp (test in a pot with hot water+temp guage and hanging the thermostat in a wire there). But be careful with the bolts that holds the housing for the thermostat(s) and take notice of direction of the vent hole on the thermostat.<br />Check the spark plugs also so they are the recommended and has correct gap and are in good condition.<br />Unless You have already done it you should change lower unit oil (replace with new gasket on lower plug also so no risk water can enter there).<br />Above should make Your outboard ready for a troublefree season.<br /><br />I would think a Seloc or Clymer manual that covers the model and Year You have will be a good investment also.<br /><br />When You post the serialnr You will get help what Year your Suzuki DT85 is.<br /><br />It would also be helpful if you post what boat you have (model, year, length, weight without outboard) and what prop you have mounted on the Suzuki DT85 You have, it is stamped on the prop if it is a orginal black aluminium Suzuki prop.<br />V1300 (13 1/2 x13 diam x pitch), V1500 (13 1/2 x15), V1700 (13 1/2 x17), V1900 (13 x19), V2100 (13 x21). As a rule of thumb 1 inch change in pitch will change RPM about 200. So if You have to much pitch you should get lower pitch prop to get more RPM at WOT. But You must have a tachometer otherwise you will work in blind.

 

[pmassey31545]

Re: sUZUKI MOTOR

The transom mount has a #. 8501 205702. Looking at other similar topics I found out that it is an 82 model. Is this correct? I was told the first # of the S.N. is the year and my hood is white with orange graphics. I pulled the fuel pump and the diaphragms look ok. The prop I have on the motor is 13x19. The boat is a 1990 Invader, 15 1/2', fiberglass V-hull and weighs about 1000 lbs. Should I expect more speed and higher RPM's? Ihaven't checked much else b/c I want to locate the problem for future ref. if needed so I haven't changed the impeller, oil, or cleaned the carbs. Waiting on a manual for those also. Also, how does a tach mount to the motor and where? And while I'm thinking of it, my speedometer registers 15 mph when sitting still. Why? I can suck on the line and hear water. Do I need a new hose and gauge? Help please!!

 

[bossee]

Re: sUZUKI MOTOR

8501 2 05702<br /><br />Yes it is a 1982 (can not be a 1992 since then the color should have been grey-green color)<br /><br />The fuel pump diaphragms does not cost much to replace so it is probably wise to change it anyway, the outboard is after all 23 years old.<br />Check brownspoint.com for cost.<br />If You try to press the fuel bulb while running, does it work better then? If so it indicate a fuel delivery problem.<br /> <br />13x19 prop<br />In my opinion that might be to much pitch (19).<br />I have on my Yamaha F115 a 13x19 prop.<br />On a 85 hp I would think it might be to much pitch. But it is hard to tell until You get a tachometer so You know what RPM You can reach with the 13x19 prop. You should aim at about 5500 RPM at WOT (Wide Open Throttle).<br /><br /><br />15.5 ft (4.72 meter), 1000 lb (453 Kg):<br />85 hp on that is probably little overpowered.<br />What does the plate on the boat say about max hp?<br /><br />Tach:<br />It is connected to the harness.<br />You need a wiring diagram, or possible someone here at iboats forum can tell what wires from Tach connect to where on harness.<br />Read this, it might help<br /> http://www.iboats.com/cgi-bin/ubb/ultimatebb.cgi?ubb=get_topic;f=30;t=001475#000000 <br /><br /><br />Speedometer:<br />Have not seen a speedometer that shows more than 0 while sitting still.<br />Usually the pressure intake that is in the water is clogged if it does not give any readings while running in the water (but that is not the problem here), in Your case it seems a problem with the instrument itself.<br />Actually a tachometer is better then a speedometer, I use the tachometer a lot and almost never look at speedometer although I have one. Maybe a second hand GPS, hand held, could be better so You get speed over ground? And You will get accurate speed.<br /><br />I had a Suzuki DT65 (1991) before, it worked great. Hope You can get Your DT85 running good.

 

[pmassey31545]

Re: sUZUKI MOTOR

Thanks for all the info. The data plate says 90hp max so I know I am close. I actually looked the boats up and the 'book' had the weight at 875lbs. I can shift the boat some when on the trailer so that is probably the correct weight. As far as a prop goes, what would someone suggest for the application. Remember, I got the larger motor for more speed/power so I could pull a skier/kneeboarder/wakeboarder. So I need good holeshot. BUT, I want speed also for when I'm "cruisin'" the river. Not breakneck, but faster than what I had. I had a guy at work tell me something about a clutch. Could that limit my speed/power also? Thanks again for all the help gentlemen.

 

[jafa]

Re: sUZUKI MOTOR

Originally posted by Paul Massey:<br /> I had a guy at work tell me something about a clutch. Could that limit my speed/power also?

Errr No , its direct gear drive. Well I think we can forget about him We are going to need those carbs pulled first , order up the relavent number of carb overhaul kits , fuel pump kit and impellor. Locate a gallon of carb cleaner and whilst we wait for the manual to arrive install the tach . The key to this is your first words "I just bought" , chances are it never had the fuel drained the last time it was ran and its all turned to gum.

 

[pmassey31545]

Re: sUZUKI MOTOR

I plan to do the work but in the mean time, can I still run the engine without harming it?

 

[bossee]

Re: sUZUKI MOTOR

Hi,<br />As I said 1 inch change in pitch will give you a RPM change about 200.<br />A 13 x 17 (or 13 1/4 x 17) would give You little more RPM. A 13 x 15 or 13 1/4-1/2 x 15 even more.<br />But I would not waste any money on a new prop until I had a Tachometer so I could see the RPM.<br />It is not good to use a prop that does not let the outboard rev at max recommended RPM range at WOT. But You do not know that yet. Just be careful until You get a tachometer, then You will "know", but based on the information You have given so far it seems a 13x17 or 13x15 prop would be better (assuming it will not over rev then). Maybe try a composite ProPulse prop, You can change blade pitch on these.<br />Check: http://www.propulse.se/english/index.html

 

[pmassey31545]

Re: sUZUKI MOTOR

Thanks for all the help. I took the boat out yesterday and it ran a lot better. I made some adjustments on the carb linkage and control cables so the throttle was wide open at WOT. It is still doesn't have great hole shot, probably the prop from what everyone is saying so I am going to go with a 13x17. Is the 13 dia. too big? should I go to a smaller dia. too or just change the pitch. I also plan to install a nem tach, speedometer, and control cables. How do I measure for the cables? Just front to back with a foot of playing room? That seems right to me. well thanks for all the help. It's coming along good. Later...

 

[bossee]

Re: sUZUKI MOTOR

13 diameter will be just fine.<br />Just change 1-2 inch lower pitch depending what present max RPM is at WOT.<br />13x17 (that is 2 inch lower pitch then Your present 13 x 19) will give you at least 400 RMP more.<br />But wait until You get a tachometer so You do not waste on wrong prop.<br />How You measure for control cables You can check out at Teleflex website. If You have uncomplicated path from control box to outboard(no sharp bends) just get standard control cables. If You have sharper bends between control box and outboard get the more flexible and<br />less friction Teleflex Xtreme cables (more expensive).<br /><br /> http://www.teleflexmarine.com/catalog.html <br /><br />(Controls)

 

[pmassey31545]

Re: sUZUKI MOTOR

10-4. I'm waiting on the gauges then I can get some more accurate info to you guys. I appreciate everything so far. Thanks...

 

[Yepblaze]

Re: sUZUKI MOTOR

A couple of items you might consider.<br /><br />If the hood is foam lined on the inside, it, or they, can deteriorate and let little bits of foam enter the carb bowl vents causing repeated, and or periodic starvation.<br /><br />Also because many of the three cylinder motors had used a pressed crankshaft they had quite a few slip causing the firing to be thrown off.<br /><br />You may want to check and mark TDC on all pistons to make sure they are evenly spaced at one third revolution.

 

[pmassey31545]

Re: sUZUKI MOTOR

I got a prop today(Sat.) and I plan to put it on Monday and try it out. I went from a 13x19 to a 13 1/2x15. Alocal dealer suggested the size. My question is this-if you drop size in pitch, from 19 to 15, should my RPM's increase or decrease. I have the same guy as earlier at work telling me that the 15 will come out of the hole better but the RPM's will be lower and speed will decrease dramatically. The dealer told me the opposite. He said I should gain holeshot and some speed and about 800 RPM's. About 200 RPM's per pitch size-down 4 sizes,19-15, up 800Rpm's. Am I correct on this. Obviously one of the two guys is wrong. Which is it. I can take the prop back and exchange if it isn't what I'm looking for so I haven't lost any $$$. Please let me know what you all think....Alos, great info on the foam. There wasn't a silencer/filter on it when I bought it so that could be one of my problems. I'll check...

 

[bossee]

Re: sUZUKI MOTOR

Hi,<br />Going from 13 x 19 (diamater x pitch) to 13 1/2 x 15 is going to increase RPM. Since You increase diameter it will not give as much RPM change (but it will not be that much lower RPM). It will probably be just fine. Larger diameter gives You more blade "area" so it can give better bite in the water but will cause more drag in water as speed increase.<br /><br />I do not know the rule of thumb when changing both dimater and pitch. The calculations is probably not that easy. But anyway You should probably expect 600-800 RPM increase in Your case.<br />Higher diameter will give more drag in the water since You get more "area" that must go trough the water. <br /><br />Also if anticavitation plate (the plate above the prop) is low, the outboard lower unit will give more drag in the water. The rule of thumb is the anticavitation plate should be level with the keel line.<br /><br />When You decrease pitch You get less "twist" on the blades so it will rev easier and higher. It will give better acceleration but possibly lower top speed. Top speed: if You by changing to a lower pitch prop, as in Your case, and You then will achieve a RPM near or at max by manufacturer recomended RPM at WOT You should have rather optimal speed also.<br />I think max recommended RPM on DT85 (at least later models) was 5500-5600 (check the Owner's manual for Your DT85).<br /><br />To Your friend: imagine You start with a 13 x 0 prop. It will take You nowhere since You have no pitch (twist) at all on the blades.<br />Imagine you had a variable prop hub so You could change pitch from control box (like in some prop aeroplanes). As You increase pitch and RPM You get better bite in the water. At some point you obviously would get to much pitch so it will not have the force needed to keep the RPM up even at WOT causing the performance(speed) to go down. It will be like trying to run uphill on 5 gear in a car.<br />It is not that complicated if You think about it.<br /><br />What is complicated with prop selection is that You can change both diameter and pitch and the combined effect is not that easy to anticipate.<br />Factors like "cup" and "rake" also has effect on prop performance.<br />There is formulas to use to try to achive a sertain effect but they are based on you have all the correct input factors. In reality it is actually often both easier and better to use trail and error method (but it can be expensive).<br />Also the type of material the prop is made of will have effect on prop performance. Aluminium, Steel or composite(ProPulse) have their pros and cons and the cost will vary much (Stainless steel props is more expensive).<br /><br />My guess is that You will actually get both better acceleration (holeshot) and better top speed with the new 13 1/2 x 15 compared to the old 13 x 19 prop You had before.<br /><br />You are obviously on the right track with Your outboard now by making the nessessary changes and service items needed to get it running optimal and reliable. Once it is in good shape and serviced properly You will probably enjoy many years use with this outboard. Despite Your outboard is 23 years old these 2-strokes can last for a long long time if they are taken care of (service etc). Actually it is better to have an old taken care of outboard then a newer outboard never serviced and neglected.<br /><br />In addition to give You personal satisfaction to get the outboard running as You want You can rely on it much better when at sea when You know it is in good shape. It is a safety thing actually.<br /><br />When You are going to change the prop on monday bring a piece of wood with you so You can place it between prop and anticavitation plate so the prop will be fixed as You loose the prop nut. Use water resistant marine grease on prop shaft when mounting the new prop and a new cotter pin. You may (or not) get trouble to get the old prop loose, it depends if previous owner has greased the prop shaft splines regularly or not. Be careful when trying to get off a prop that is stuck on the prop shaft (use WD-40 or similar and wait and hopefully it can come off). You may need some special tool (puller? but that would probably ruin the prop) to get the prop off, or try a plastic hammer if it is stuck on prop shaft.<br /><br />

 

[pmassey31545]

Re: sUZUKI MOTOR

Hey,<br />Thanks for all the info especially the article at the end of the reply. That was great info. That is the perfect answer to my question. So the long and short of it is my friend was right AND wrong. It doesn't really matter. I am taking the boat out Monday and I'll let you know how it ran compared to before. The old prop came off very easy and the engine is pretty clean so I can only assume that it has been taken care of some-to what extent I don't know. Whatever the case is, I aim to get it running as good as possible. Later...

 

[pmassey31545]

Re: sUZUKI MOTOR

Another question-I bought plugs today for the motor. The problem is the plugs that are in the motor are B8HS NGK's. The plugs I got areB7HS NGK's. The man told me they would burn hotter. But, Just like a car I think this could cause me to burn a hole in a piston. Any thoughts?

 

[bossee]

Re: sUZUKI MOTOR

Personally I would only use the recommended spark plugs according to the Owner's manual.<br />With correct "gap" of course.<br /><br />Try to see if You can find what Champion spark plugs can be used (that correspond to recommended NKG spark plug) if You can not find NKG B8HS.

 

[Triton II]

Re: sUZUKI MOTOR

The NGK site lists the plug at:<br /> http://www.ngksparkplugs.com/apps/watercraft/results.asp?id=1510&type=reg <br />There's also the V-Power plug at:<br /> http://www.ngksparkplugs.com/apps/watercraft/results.asp?id=1510&type=v <br />So I'd be asking your dealer to bring in the correct plugs - they're available.