New to Forum - 87 DT20

[Uncle Buck]

Hello Everyone

It's my first post on the forum,
My name is Gord and i live in Hamilton Ontario, Canada
i hope to be of help to others as much as i can...

I enjoy fishing and that's why i have the boat....

I recently picked up an 87 Suzuki DT20 outboard

I can't get the primer bulb to harden?

also flooding the plugs, i've adjusted the float a bit and it's helped, but it still won't idle

the carb is a Mikuni Carb and i've googled it but can't find any info on it...
anyone know how to adjust the carbs? I had a buddy who's an outboard motor hobbyist (old johnny-rudes) look at it, and we couldn't figure it out...

also had it on the boat this weekend and was only getting about 6mph out of it...

it has good spark and 110 compression on top and 106 on the bottom
boat is a longshaft, but the motor is short shaft so i know that will affect performance, but i should get better speed then that

motor sounded like it was working hard also...

any help would be appreciated

Thanks
Gord

[mitch]

Check the fuel pump diaphram that it has not got a hole letting fuel directly in to crank case.

I doubt that the float level has altered check that is right other wise it could be running too lean an burn a hole in a piston.

But i would start with the fuel pump first .

Then the needle and seat to see if it does not have crap in it.


Mikuni carbs are on everything motorbikes outboards they are simple as hell and work great.

What size boat is it on. as it should get up on the plain at least 20 mhp

[Uncle Buck]

Boat is a 16.5 foot aluminum fishing boat. Boat is setup as a side console, but i'm running it with the tiller...



The Diaphram looked ok.. didn't appear to have a hole in it...

the low speed jet is the screw at the top behind the air scilencer



the bottom screw in the float bowl, is that only to drain the bowl?
it had a big indentation on the screw of where it tightened into



where is the high speed jet?

[mitch]

geez you need a bigger motor that's a lot of boat that you are trying to push but just the same it is a good looking boat.

you need at least a 60 hp

[Uncle Buck]

Boat is rated for a 50HP

problem is no $$ for a 50...

the little 4.5 johnnyrude pushes it to 4mph

so the 20 suzuki should bring it to 15mph i think?

for the time being i have no choice

[Uncle Buck]

Found the problem, hole in the diaphragm...

does anyone know the sierra part numbers for the front and rear diaphragms for the fuel pump? Suzuki DT20

also for the gasket that goes between the engine block and fuel pump?

pump looks identical to a yamaha pump (Mallory# 9-35300) my marina is unable to cross reference mallory with sierra and the closest suzuki dealer is a 2 hr drive...

any help would be appreciated

Thanks
Goran

[mitch]

Whoa you are talking about 2 different things here the sierra ( efi )pump is electric you are talking about a crankcase mikuni pump there is not a 87 20 hp on the boats net site as maybe the USA did not have them imported .................................................. .................................................. ............................ but
HAVE A LOOK HERE

Suzuki Marine Outboard Parts 1992 DT25C FUEL PUMP Diagram

THIS IS A 25 HP pump is that what you are talking about. GOOD PRICE AS WELL

[Uncle Buck]

This is what my fuel pump looks like...



Mallory # 9-35300

This what the diaphragms and gaskets look like...
only need 1 of the gaskets that has the big hole in it...
it's a 4pc kit...not 5 as shown



Sierra # 18-7787

This is what the gasket looks like that i need



mallory part# 9-35345

any ideas on the sierra#? my local marina is only able to order from sierra

[mitch]

it is just a mikuni pump have a look at link on previous post you can get it from boats.net kits about 11 bucks
mitch