Suzuki DF70

[Meggacatz]

I have a 16FT Key Largo with a Suzuki DF70 (fourstroke) installed on a Bobs Machine Shop jack plate. The motor is stock except for a same size as OEM stainless prop and regularly use to be at 5000 rpm / speed was about 40-41 GPS. Twice I have had the motor at a local & often referenced Suzuki repair shop.<br />I had water in the fuel and it filled my fuel/water seperator which allowed water to pass (stoopid Tempo? brand crap). I emptied the entire tank and refilled with fresh gas. He has replaced all the filters and checked/tuned up the engine and the engine runs fine at idle and a little above. For some reason when I put it on the water it won't exceed about 3000 rpm WOT. This gives a speed of 14 MPH. The RPM does not seem to be limited by the engines computer (safety feature). When I raise the prop out of the water while traveling WOT 14MPH the engine instantly goes to pegs around 7000RPM and I drop the throttle and jack plate to slow the prop speed. It seems like it has no power with a load on the prop and we don't understand why.<br />I have removed the anti-siphon device and installed a new Racor fuel filter with the see-thru plastic contaminant check but performance didn't change.<br />I would liken the problem to be similar to the transmission slipping in your car. The engine is tuned and runs great but the greater the load and/or more performance you demand, the more the transmission slips. I know it's a stoopid analogy but it is the best description I got for my problem.<br />I'm checking for air leaks in the fuel lines now.<br />Any help or suggestions would be appreciated.

 

[DanMcK]

Re: Suzuki DF70

Hello Meggacatz, I,m not sure if your boat has a built in fuel tank. If it does, one of the most overlooked problem causer is the screen which is on the bottom of the fuel pick up tube. Small particles get stuck in the screen, restrict the flow and generally drive everybody crazy with performance problems. The Racor is the way to go, I have one, worth the extra money. My screen clogged up so many times I finaly removed it and let the junk come up in the racor. Good luck.

 

[Meggacatz]

Re: Suzuki DF70

DanMcK - I just pulled the screen and it's clean. No junk at all. I pulled the primer blub and the reused fuel line between the Racor and the engine. I'm trying to test the priming blub and hose connections to see if air is being drawn in. Any help about testing the bulb would also be appreciated. This is frusterating.

 

[JB]

Re: Suzuki DF70

Hi Meggacatz,<br /><br />Welcome to iboats. <br /><br />Your dealer replaced both low and high pressure filters?<br /><br />It seems strange to me that the dealer didn't test the engine under load. You may be down a cylinder. <br /><br />Inspect your spark plugs and do a compression check. All cylinders should be within 10 or 15psi of each other. <br /><br />Disable each plug, in turn, at idle. If disabling a plug doesn't cause a drop in rpm that cylinder is not making power. Could be spark or a clogged injector (they don't like injecting water).<br /><br />Have your dealer put it in a test tank with a wheel or, better, on a dynamometer and test it under load.<br /><br />Once you get it fixed, reprop it for 5800rpm WOT.<br /><br />Oh, and by the way, Tempo tanks don't "make" water. Moist air in any tank will get condensation. I have used a 24 year old Tempo tank with my DF70 for 4 years, and I replace my filter/seperator cartridge annually.<br /><br />Good luck and let us know how it comes out.

 

[Meggacatz]

Re: Suzuki DF70

The Suzuki dealer/repair shop replaced both the high & low pressure filters in addition to the fuel pressure regulator in addition to all the needed gaskets etc. A compression test was:#1 200, #2 198, #3 205 and #4 203. Engine is a 1999 and has 270 hours. IAC was adjusted to 20% warm. The prop would turn about 5200 when new but now seems to just get 5000. I think it might be below 5000 as I only have 720 minutes at 5000+ rpm but 2270 minutes at 4000-5000 rpm. I have read about the rubber propeller hub may be getting a little worn so I'll check it tomorrow after work. Besides I can check the prop to verify the size and pitch. I'll also try the pull the plug wire and watch for a drop. The engine idles very smooth (like when it was new) but I'll try.<br />The worst part of this experience is that since it was new (04/99) the engine and boat have been great. I was out at least once a week and never had a problem. But my son was born last May and I had to change my work schedule and now I can barely find time to go. Since then I've had these problems because of the water. So everytime I get a chance to get out now, the engine runs poorly and ruins the day. I'm not heading out this Memorial Day weekend because of the crowds and traffic, but I would like to figure out what is wrong. I'll talk to the mechanic again in the morning.<br />I appreciate the timely responses and found this board while researching these problems. I'll keep watching, explore the board and contribute in the future.<br />THANX <br />Your "new to the board" friend<br />Brian

 

[lakensea]

Re: Suzuki DF70

It sounds like you have a fuel delivery problem. You need to check fuel pressure at the fuel rail under load. Was the VST disasembled and fuel pump screen checked? If the water was so bad that the regulator had to be changed, then the high pressure fuel pump should also have been replaced.

 

[clanton]

Re: Suzuki DF70

Check fuel pressure at full throttle, boat in water in gear. Were the valve adjustments checked? Sparkplugs changed? Gear oil checked? Any codes when computer check was done? The Racor also needs to be checked for air leaks.

 

[Meggacatz]

Re: Suzuki DF70

I believe the high pressure fuel pump was replaced the last time it was at the shop (forgot to add this before). I was told maybe an injector went "bad" or was clogged. The mechanic/owner of the Suzuki dealer I've been working with wants me to call him (at home) from the water to let him know what it does. I have faith in him and he seems to be thorough.<br />Today I installed new fuel hose and primer blub and checked/PM'd the prop. It's a stainless 13 1/4"x17. The boat came with an aluminum Suzuki prop 13 1/4"x17 (item V1700). So I assume that if the engine continues to achieve WOT RPM of 5000-5200 (when repaired) then I need to switch props to a 13 or 15 pitch to increase RPMs?<br />I got futzing around too much with it tonight and couldn't get it to the water before dark, so tomorrow I'll put it in the lake & see how it does. Thanks for the help, it has given me several things to talk with the mechanic about and allows me to check things before giving it to him (saves me some $$). Y'all have a good night.

 

[Meggacatz]

Re: Suzuki DF70

I put the boat in the lake this evening. It was rough at idle and the low RPMs under load. Not enough to send me back to the dock but not as good as in the driveway last night. When I got out to the open water from the no wake zone, it sounded like it wanted to run properly, smoother (almost). Accelerated smoother to almost 4000 RPM but then I heard a muffled "pop" from under the engine cover. Just once & not loud. The engine then would not run over about 2700 RPM. After that the engine began to surge and ran poorly. I limped it back in with it continuing to surge, causing RPMs to drop or rise between 200 & 400 RPM while running at just over 1000 RPM. Had me worried about getting in.

 

[JB]

Re: Suzuki DF70

Hi, Catz.<br /><br />We can't help you if you don't take our advice.<br /><br />It is a bad idea to take out an engine that obviously has problems. Terminal damage could occur.<br /><br />Please get the engine tested under load in a safe environment. Verify that all cylinders are making power and that fuel supply is adequate.

 

[pdspeh]

Re: Suzuki DF70

My 2001 70 Evinrude (DF70) did the same thing 3 weeks ago. ful throttle was bogging at 3000rpm. the 1st three times I took it out ...stayed off the throttle, let it run for a while ,like all day ,and now it's fine...fuel starvation . reading this thread helped.Thanks

 

[Meggacatz]

Re: Suzuki DF70

JB - I wasn't trying to go against anyones suggestions. My mechanic told me to put it in the lake, run it gently ,and call him from the water to let him know if it acted any differently. Now it surges (when it never did before) and maybe the problem can be traced to one of the sensors now. I believe I had multiple problems: a failed fuel/water seperator that allowed water to pass to the other filters & pumps in the engine, maybe an air leak in the fuel line or bulb, a problemed sensor that was masked by the other problems at higher RPMs.<br />The motor is back at the shop today and we'll see what the computer and mechanic say. Again I appreciate everyones help. Any other suggestions or comments would be appreciated.

 

[Meggacatz]

Re: Suzuki DF70

WATER. Something so cheap has cost me so much aggravation. Water in the fuel. Worked past most of the filters and recontaminated the entire fuel system AGAIN. Saltwater corroded some of the fuel delivery system. After some intense cleaning and part replacement, the engine runs great.

 

[Don B.]

Re: Suzuki DF70

Meggacatz,<br /><br /> I am experincing the same symptoms with my DF 50. It will not run above 2000 or so RPM before it starts running rough and wants to die. I got it back to the slip and if anything it has gotten now to the point where it won't even idle. I have a service order in to look at the engine and they are about a week behind and this is going on three weeks. I have been told that Suzukis are very susceptible to water injestion problems but frankly the clear filter inside the engine looked clear as a bell and I showed the gas in it to the Suzuki dealer and he felt the same. I truly think I am having fuel line problems. WHat the heck connector do these Suzukis use ? I have been to Boaters Works and West Marine as well as the dealer and have yet to see what a Suzuki two plug connector looks like. They all want to sell me the danged single line brass one which is not what my DF50 has. The one that came with the boat went bad last year and I replaced it with a Evinrude style. It worked at the time but I have learned since that the wrong style can work for awhile and than it goes bad. And if this is not bad enough I have 6.5 gallon plastic duratanks with built in two prong male vented connectors built in and I am not sure what they are either !!<br /><br />-Don B

 

[Don B.]

Re: Suzuki DF70

Meggacatz,<br /><br />After about a month the repair shop got to my boat. It had a bad plug. The plugs were replaced last year at tune up but you know how that goes.<br /><br />I would have tested the plugs myself but since I was having so much trouble determining if I had the correct fuel connectors going to the tank and the engine we decided it would be smarter to call in an expert.<br /><br />Of course it is weird the plug went bad and I hope it is not symtomatic of some other problem.<br /><br />And by the way the repair shop told me that Suzuki has put out a bulletin that no starting battery is to be connected to the Suzuki DF 50 with wing nuts. They want the battery cables nutted down with washers. I guess a loose connection can cause voltage spikes and kill the unfiltered computer.<br /><br />Have a good summer,<br /><br />Don B

 

[Don B.]

Re: Suzuki DF70

Wow !! I just got off the phone with the repair shop and he only charged me $136.78 for in slip service of changing oil and filters for oil and gas separator and also 3 new plugs.<br /><br />That sure makes me happy !<br /><br />-Don B

 

[Meggacatz]

Re: Suzuki DF70

AH - HA !!<br />I believe I found where I was getting water into my fuel tank. The access panel to get to the fuel tank in beneath my center console. The baitwell is on the front of the center console. If the bail well is too full, it spills over the sides and can run beneath the center console. The sending unit and fuel pickup is on top of the plastic fuel tank. It seems that the plastic fuel tank may have warped slightly. The fuel sending unit was rusted very badly and the gasket had a gap between the sending unit and top of the tank. I believe the water was seeping (flowing) in from the overflowing bait well. It could explain how I got "gallons" of water in the fuel tank. I replaced the sending unit and sealed (5200) around the edges of the unit after I secured the unit in place. I also fully sealed the access panel as I don't need access to the top of the fuel tank unless something else breaks. In that case I can just peel off the panel and 5200 and replace it.<br />I appreciate the help and ideas.

 

[louisp]

Re: Suzuki DF70

Don B., I understand your confusion with the fuel connection. I bought one of the DF70's here on iboats and the motor came with the Yamaha looking connector, but the packing included the single 'airchuck' looking Suzuki connector. Boater's World had no Suzuki connections nor did they know what I was talking about. It seems the learning curve for the Suzuki's is still on the way up. Best to you, Lou.