Suzuki DT55 limp mode? Low RPM's

Big_worm81

Seaman
Joined
Aug 8, 2013
Messages
70
Re: Suzuki DT55 limp mode? Low RPM's

So in case anyone cares about stuff other than engines ... here is a photo of my RHIB with the new red LED's I installed. Two are about 2" off the deck and light the main deck area. One is in the front of the console about 12" off the deck and lights under the bow seat where the gas can lives. The last LED is mounted under the forward lip of the bow seat (at the crook of your knee while sitting). It is pointed straight down and lights the small area in front of the seat but before the bow locker. Its red glow dimly lights the bow locker area as well which is a nice bonus. The lights are Lumitec Newt Livewell/Accent Lights, they draw 30mA each and are completely waterproof.

2qthbg3.jpg


Now before anyone jumps down my throat; no these lights do not represent a hazard to navigation. They will not confuse other boaters at night who can't tell the difference between a red cockpit light or a port hand navigation light - because I won't be running with them on. These lights are for loading and unloading at the dock and for if I drop something on the deck and can't find it.

While working with the power side of things I realized I would really like to move the battery to the console. It would free up some space on deck, shift some weight forward (always nice) and really clean up the looks of the boat. Downside is the factory battery set up on the boat comes with 8AWG wires from the starter and are only about 5 feet long. I just looked at the harness a little closer and it looks easy enough to change the entire wire out. I have some red and black Ancor 6AWG tinned copper marine boat wire in the garage so I guess I'll go for it.

In the picture you can see I have added a battery isolation switch and a Blue Sea WeatherDeck 4308 eight gang switch panel to the console side as well. Will be nice to have switches for things like VHF, Navigation Lights, Cockpit Lights, Cigarette Lighter, Bilge Pump ... without having ugly mis-matched switches all over the place.

Anyway, something different from me for a change.
 

Big_worm81

Seaman
Joined
Aug 8, 2013
Messages
70
Re: Suzuki DT55 limp mode? Low RPM's

Does anyone know what purpose this hose serves? Equalize air pressure at inlets to the three reed valves? Its like a closed loop and doesn't serve much purpose that I can see.

5v11kx.jpg
 

Big_worm81

Seaman
Joined
Aug 8, 2013
Messages
70
Re: Suzuki DT55 limp mode? Low RPM's

First coat of Suzuki paint ... I am hugely impressed with the factory match.

izt4bb.jpg
 

99yam40

Fleet Admiral
Joined
Sep 7, 2008
Messages
9,135
Re: Suzuki DT55 limp mode? Low RPM's

looking good.
Hope it runs as well as it is looking
 

Big_worm81

Seaman
Joined
Aug 8, 2013
Messages
70
Re: Suzuki DT55 limp mode? Low RPM's

There, all painted up pretty and all the junk bolted back on. Cleaned the carbs and installed new needle valve assemblies and gaskets. Now I wait for thrust washers for the bottom end ...

sqp278.jpg
 

James R

Commander
Joined
Feb 1, 2007
Messages
2,679
Re: Suzuki DT55 limp mode? Low RPM's

If you fasten her down you can check the compressions before installation. Looking good.
 

Big_worm81

Seaman
Joined
Aug 8, 2013
Messages
70
Re: Suzuki DT55 limp mode? Low RPM's

Well ... I love the smell of two stroke in the morning.

Bottom end thrust washers arrived and I put the lower unit back together. Checked the end play on the propeller shaft. It was 0.011" and the tolerance was 0.008-0.016" so good to go.

New water pump bottom plate and impeller.

Lowered the power head down on chain fall and spend a good few hours messing about with the various wires.

Compression test results. 125 top, 118 middle, 125 bottom.

Gapped plugs.

Dumped premium fuel from tank into my van and mixed a new batch of 50:1 premium gas with TCW3.

Connected the fuel line, pumped away on the fuel ball and she fired right up. It took several attempts to get it to stay running, eventually I just used a wee bit of high idle to get it to catch then dropped back to idle.

It's smooth and sounds nice. When it first starts it sounds like it's running on two cylinders then it sounds like the 3rd one cuts in after a few seconds. Dad and I thought that was strange.

I do have one issue so far. There is a very very small water leak at gasket between cylinder head and head cover plate, at area of middle spark plug.

I guess I will order a new head gasket and head cover gasket, then reassemble with silicone gasket as well ... Unless anyone has any other ideas.

I will try to upload a video after dinner.
 

mphelle8vld

Petty Officer 1st Class
Joined
Aug 17, 2005
Messages
321
Re: Suzuki DT55 limp mode? Low RPM's

Job well done! Can't wait to see a video of it jumping waves.
 

99yam40

Fleet Admiral
Joined
Sep 7, 2008
Messages
9,135
Re: Suzuki DT55 limp mode? Low RPM's

I do have one issue so far. There is a very very small water leak at gasket between cylinder head and head cover plate, at area of middle spark plug.

I guess I will order a new head gasket and head cover gasket, then reassemble with silicone gasket as well ... Unless anyone has any other ideas.

I will try to upload a video after dinner.

Mark were the leak is so you can inspect surfaces after removing.

Might try re-torquing all the bolts after the 1 run to see if that will help,

Did you check straightness of surfaces or resurface any of them while you had them off?
 

James R

Commander
Joined
Feb 1, 2007
Messages
2,679
Re: Suzuki DT55 limp mode? Low RPM's

I have been watching and see that you are doing a good job. I don't think I would entertain using silicon as a sealant. It doesn't last. I would recommend the OMC Evinrude/Johnson gasket sealer. It works. I have had similar water leaks on Suzuki and other motors so as a precaution I always use the OMC sealant. I have not found anything similar to the OMC product.
 

Big_worm81

Seaman
Joined
Aug 8, 2013
Messages
70
Re: Suzuki DT55 limp mode? Low RPM's

Thanks all. I don't need to mark anything, I have photos of the entire process and every piece from every angle imaginable. It looks like the head is scuffed or scored where the machine shop clamped to remove the broken stud and insert the heli coil. I wasn't planning on using strictly silicone, I was planning on using a gasket making product like OMC or RTV. I'm going to fix this issue for sure but I'm not sure if it will be this summer or not. It's just a pin hole jacket water leak which IMHO poses minimal to zero risk to the motor. I have a ton of other work to do on my 3288 including re-packing two shaft, installing propane stove, installing house battery bank, installing charger and alternator distribution system, rebuilding radar arch due to rot ..... Etc etc .... But that's another thread!!

I will post back with break in video, and other info with my plans for the motor later.
 
Last edited:

James R

Commander
Joined
Feb 1, 2007
Messages
2,679
Re: Suzuki DT55 limp mode? Low RPM's

Good deal but RTV wont stand up either. Good luck with reconstruction.
 

Big_worm81

Seaman
Joined
Aug 8, 2013
Messages
70
The boating Gods have been good to me. 1991 DT65, doesn't run. The serial on my 55 is 531168 and the 65 is 131168 ... Twilight zone!!! Anyways there are a ton of sweet parts on this motor including a lower end without so much as a scratch. Once I get the 55 running good I'll make it a 65 by swapping carbs if I can get them apart for cleaning without breaking anything. All for $200
m8z8kw.jpg
 

Big_worm81

Seaman
Joined
Aug 8, 2013
Messages
70
So I thought I had a rant on here about a failed boating attempt ... perhaps it was deleted because of too much foul language regarding the horrible Innisfil Beach launch near Barrie, Ontario. Anyway ... some trouble shooting has determined that the timing is quite retarted (not trying to be funny, the timing is the opposite of advanced). The engine wont go over 1800 RPM and seems to be misfiring. I changed CDI computer to no avail. What else should I swap out ... I have this parts motor with all kinds of good parts on it.
 

mphelle8vld

Petty Officer 1st Class
Joined
Aug 17, 2005
Messages
321
I remember the rant, nice find on the parts motor. Seems like it had no electrical or carb issues before the rebuild, I would re-check all the electrical connections. What's the timing at idle and is the timing advancing with throttle?
 

Big_worm81

Seaman
Joined
Aug 8, 2013
Messages
70
I will recheck the electrical connections this afternoon, and maybe swap out the gear counting coil and see if that makes a difference. I can't tell how far retarded the timing is because it's off the scale. The flywheel is keyed to the crankshaft so that's pretty straight forward ... No mechanical timing to be set. The timing does advance with increased throttle.
 
Top