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Suzuki 85HP help needed please

P

pommy

New member
"Hi,

I have bought my firs

"Hi,

I have bought my first boat and have two issues i'd appreciate some help on.

Firstly - how do you know the age/model of the motor?

And secondly, which I probably need the answer to the first for is power - the motor is seriously lacking power.

It runs peferctly in and out of the water, the prop is ok condition but I am getting other boats with 20-25 HP motors flying by me.

It's a 14' Ski boat and has the acceleration of a lame tortoise.

If I drive slowly for a while and then stop, it is really hard to start as there seems to be a build up of 2 stroke. If I blast this out by revving hard with the bypass button pressed in it clears with lots of smoke and then runs perfectly again (just with no power)

If you can help me i'd appreciate any input.

Thanks in advance!"
 
Check to see if you have a goo

Check to see if you have a good ( 7/16" ) spark at each cylinder.Make sure you have fuel coming up each main jet ( flash light required ). You have of course checked for even compression.
 
"Ikia - thanks for the tips -

"Ikia - thanks for the tips - all have been completed already.

The motor runs smooth as can be, not lumpy, doesn't miss on idle.. it actually purrs along great.

If you go from zero to hero with the throttle it wouldn't spill a cup of tea in your hand though???"
 
OK----- there was no indicatio

OK----- there was no indication of your expertise in the first post. So check into whether this motor has the correct prop for the boat that it is on or maybe the boat has problems ( water logged ) Have a competent dealer run the motor on a dynomometer to check and see if power output matches the numbers on the cover.
 
"Cheers mate - I actually have

"Cheers mate - I actually have no specific boat knowledge as such - but I am a motor mechanic, so it not completely new to me.

The boat is running dry, I know that much - but how do you know if the prop is correct for the motor?

I suppose I will have to take it to a mechanic then - I was just trying to find out if anybody knew anyting I could try myself.

My guess would be that the oil/fuel mixture is out as I've have two strokes before and getting that balance was crucial for power. (Only this one self-mixes..?)

Thanks for the help though mate, much appreciated."
 
post the serial number

it i

post the serial number

it is the fuel pump and carbs need rebuilt

then you need to sync and link it
 
"Hi,

the Details from the

"Hi,

the Details from the motor are:

DT85 - 8501 - 308253

Also, the motor runs smooth and is not starving of fuel so the pump/carbs will be fine.

Thanks very much for the help so far!"
 
"I bought a 16' CC boat la

"I bought a 16' CC boat last fall with an '86 DT-85. The boat could hardly get on plane with a top speed of 25 mph. The boat was over propped !!! Ther is a number on the prop (such as 13x19). Mine had a 19 pitch on it, it now wears a 15 pitch and the boat does 34 mph. I also agree with Just In Time. It wouldn't hurt to check your carbs, especially after what you said in your post about having to hit the choke(you called it a by pass). Replace the fuel pump diaphragm and o-rings, take the carb bowls off and check them, blow out the jets, and don't forget to replace the water pump impeller. That should be done every season, (or at least every other at the most)."
 
"Great i'll go ahead and g

"Great i'll go ahead and get that prop checked right away!

Oh I wasn't referring to the choke by the way - under the ignition key there is a small push in rod which disables the gearbox and allows you to rev the engine.

Without this the motor has to be in gear - hence the by-pass term I used.

The choke is magnetic and on the key barrel, you push it in and turn on this model to engage it.

I'll post back the prop size.

The guy who sold me the boat though had 2 people skiing off this prop?... hmmm

UPDATE - 13 1/4 x 17 it says on it?"
 
Prop should be fine at 17 pitc

Prop should be fine at 17 pitch...stupid question but are you running pre-mix in a motor with an oil tank and fully functioning oil pump?.....just might explain the build up of 2-stroke??? Not trying to insult your intelligence but it can happen.

What happens if you hit the choke while acceleratiing? Boost in performance or cuts out??
 
"Hi Andy - i've been out i

"Hi Andy - i've been out in the boat and put four 25L tanks through it, the oil tank on the front of the motor went down accordingly. If i hit the choke when warm it is even more sluggish and runs rough...

When you say pre-mix - I'm assuming you mean mixed 2 stroke and petrol? Well the motor does the mixing? Sorry if I got you wrong."
 
"Hi Pommy, the choke test sort

"Hi Pommy, the choke test sorta rules out running weak....could be reeds maybe???"
 
"Hi Andy,

So you think the

"Hi Andy,

So you think the carbs also?...

I guess I should take a look at them then although this motor is immaculate under the cover.

Blocked carbs in my experience with cars would not allow the motor to run at full thottle - there would be a definate point where the power is lost.

This motor "appears" to be flat out, runs perfectly but has almost no acceleration?!

I will probably do the carbs as a matter of course now - but my gut feeling if that it's not the problem.

Cheers!"
 
"I'll have to have a bit o

"I'll have to have a bit of time to take the carbs off - but I did just take the plugs out.

As you can see there is a lot of oil at the plug holes, which kind of confirms my idea of too much oil = loss of power?
150971.jpg
hole"">


- what do you make of the plug condition?


150972.jpg
150973.jpg
2"">
150974.jpg
3"">

Also, if you go here:

http://s103.photobucket.com/albums/m143/onlythebestsells/?action=view&current=Movement.flv

I have uploaded a small clip of the throttle movement - first with the pin pushed in, then after the click, is with the box engaged.

And here is the motor flat out on smooth water - the "Tone" of the motor says it all.

http://s103.photobucket.com/albums/m143/onlythebestsells/?action=view&current=Flatout.flv

"
 
"Top plug looks crappy, others

"Top plug looks crappy, others also dirty, just not as dirty. I would replace them all.Check compression and let us know. Boat engines are not like auto engines, I work on both !!! Outboards have low, mid and high speed circuits, all separate. One jet gets clogged at a particular rpm range and then you're running on 2 cylinders. The new ethanol fuels are murder on small engines and outboards and it deteriorates quickly. If boat was stored without Stabil, fuel and carbs are the likely suspects.Boat will not get out of its own way on 2 cylinders!!! Check compression, then do fuel pump and carbs. Parts are cheap, all you need is carb bowl gaskets and fuel pump diaphragm and o-rings. Check Brown's Point online for parts and prices."
 
Great stuff - thanks!

So yo

Great stuff - thanks!

So you would actually go and strip them all down rather than try a carb cleaner first?

And do you know why all that oil is there?

P.S - it's all the same plug in different lights.
 
In order to clean a carburetor

In order to clean a carburetor it MUST be torn down.This spraying carb cleaner into the throat does nothing.----- There is no " mechanic in a can "
 
Now all that oil on the plugs

Now all that oil on the plugs may mean that the thermostat is no good and it is running too cold.It may mean that you think the motor is running on all cylinders when in fact it is not.Hook up a timing light to each cylinder as you run to full throttle and see if indeed it is firing.
 
"Ok well I got some plugs - gu

"Ok well I got some plugs - guessing they are pre-set as they look like the others?

Regarding the thermostat, if I start the motor from cold - about 60 seconds and the water that squirts out is bathtub warm - what does that indicate?

Thanks for everything so far!"
 
"I was just thinking, as this

"I was just thinking, as this is my first boat - maybe it IS running as fast as it should and the boat is just an old heavy glass boat that's had it's day...

151041.jpg
boat
 
"Well , plugs that foul are no

"Well , plugs that foul are not firing and that indicates weak spark. Many boat owners have been surprised by their pride and joy which had hundreds of pounds of water soaked into the foam under the floor.Had someone once who gave me the what are you talking about look. Then some months later came over to say " you were right i got rid of the foam , rebuilt the stringers and frame work and now the boat flies over the water " . But some people are slow to learn and tbat will never change."
 
"The adjustment is on the oil

"The adjustment is on the oil pump which sits at the base of the oil tank, there are a couple of marks to line up so a manual or jpeg from one of the guys here will help.

That plug looks like it isn't firing well or at all and the motor looks the right size for the boat....did the girl come with the boat?? :) :) Chuck in some new plugs but if the problem is a coil they won't help."
 
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