Mystery engine

[SamW556]

I have what would appear to be a 1976 35hp johnson. The lower unit has the serial number 35r76g, and appears to match that. However when I use that number to find parts for the engine, none of the oem diagrams look like my engine. I even bought a replacement fuel pump but failed to notice it had only 2 connections, where the original had 3. I've looked through countless oem diagrams from the 70s up to the 90s, and from 5hp all the way up to 50, nothing seems to match. Can anyone help? Some serial numbers I've found include mx340913, 326713, 335635, 436366 if that helps.

 

[racerone]

The fuel pump mounts directly over the PRESSURE pulse port.----So therefor the fuel pump is not the correct one and no surprise to me.----These simple pumps are not well understood in my opinion.----.----It does work with a hose to the pressure port.----And this powerhead has electronic ignition.----So it is not a 1976 powerhead.----Powerhead might be a 77 or 78 year and possibly newer than that if exhaust tuner was also changed-----It should be easy to find parts as these engines and many parts ( except for the block ) were the same.

 

[saltchuckmatt]

Carb with plastic parts is from a newer engine.

The motor is a Frankenstein.

 

[SamW556]

Carb with plastic parts is from a newer engine.

The motor is a Frankenstein.

That's kinda what I was thinking. Do you have any info about that particular carb? I can't seem to find anything about it online.

 

[SamW556]

The fuel pump mounts directly over the PRESSURE pulse port.----So therefor the fuel pump is not the correct one and no surprise to me.----These simple pumps are not well understood in my opinion.----.----It does work with a hose to the pressure port.----And this powerhead has electronic ignition.----So it is not a 1976 powerhead.----Powerhead might be a 77 or 78 year and possibly newer than that if exhaust tuner was also changed-----It should be easy to find parts as these engines and many parts ( except for the block ) were the same.

So the block for the 77-78 year motors have only one pressure port and it is behind the fuel pump correct? My motor has that as well as a separate connection with a hose...

 

[racerone]

Correct , the 76 was mounted directly over the pressure port , with a hose for fuel in and one for fuel out.

 

[SamW556]

Correct , mounted directly over the pressure port , with a hose for fuel in and one for fuel out.

Mine also has this, which I assume is another pressure port. It was connected on the old fuel pump. The one in the picture is the replacement I bought with only the fuel in and fuel out. It still runs strangely enough.

 

[racerone]

It appears that around 1990 ( 30 HP prop rated ) they fiddled with different a fuel pump.----With that extra pulse port for some strange reason.----Using 2 ports would make no difference in engine operation.----You can block off the extra pulse port.

 

[SamW556]

It appears that around 1990 ( 30 HP prop rated ) they fiddled with different a fuel pump.----With that extra pulse port for some strange reason.----Using 2 ports would make no difference in engine operation.----You can block off the extra pulse port.

Thanks. Could that mean the block might be from around that year?

 

[racerone]

Could well be.----These motors are very well built in my opinion.-----Lots of them around.----Just picked up 2 more myself.----These are the 28 HP " specials " and are good parts motors.--Picked them up for next to nothing.--In 1990 the CD powerpack was under the flywheel.----Which is external on yours.----With 40 year old motors of this type anything is possible. ----Folks today want the expensive " can not be repaired " 4 stroke outboards.----Some shops refuse to work on older motors or 2 strokes.----So those who are handy can go do some enjoyable boating on a much lower budget !

 

[saltchuckmatt]

Manual primer is 85ish or newer and superior in every way to a choke. Learn how to use it.

Best to get it idling well and not long (water pump/coolant flow). If it checks out stop, compression check and full evaluation of outboard.

Great outboard but might have to De-Frankenstein some things to make it run correctly.

Lots of help here but many here like to give you clues so you learn.

Racerone is the top banana.

I'll be lurking.

 

[racerone]

That manual primer can be fitted to any motor from 3 to 300 HP.--From 1960's and newer.----Agreed on a 50 year old motor a complete evaluation needs to be done.

 

[SamW556]

Thanks for all the help. I've actually had the boat for a while but never really looked into it because it runs ok. It's got 115 psi on both cylinders, pees water fine. I've taken it on the water many times and it'll take my 14 footer with 2 people about 25mph. It seems like the carb might be from a 15-25hp or somewhere in that range. Any advice for how to figure that out / find a compatible one?

 

[racerone]

Take the carburetor off.-----Inspect.----Report the number you find on the high speed jet.-----Yes this powerhead was marketed as a 20 hp for many years.

 

[SamW556]

Take the carburetor off.-----Inspect.----Report the number you find on the high speed jet.-----Yes this powerhead was marketed as a 20 hp for many years.

High speed jet/orifice reads 44.

 

[Nordin]

I think those fuel pumps with a hose fitting to the pressure port is a retro fit pump if you convert from VRO to regular premix system.
The VRO pump take pulses from the crank case with a hose connected to a fitting at crank case.

 

[racerone]

VRO was never offered on that 2 cylinder block.----I can't believe the number of new fuel pumps sold for these motors.-----Very little can go wrong with these pressure driven pumps.

 

[Nordin]

Yes, agree but the 2 cylinder 40 and 50Hp had VRO.
I have converted some 40 and 50Hp with that kind of fuel pump.
You are able to put that pump at a 35Hp too.

 

[racerone]

Some of those pumps are good enuff to run a 20 HP 2 cylinder and will also supply a 100 HP V-4 !

 

[flyingscott]

They went to the bigger pump on everything later in the 80s or early 90s. usually used a reducing T on the smaller engines. a cost cutting measure I think.