Starting and maybe restoring old Mercury 402 40hp

[oldcab]

hi everybody, I need some help please...
just got this engine from a boat project
trying to work out if this will start

tried to do a compression test, but it's very hard to turn with the compression tester,
and I noticed the prop will always turn even in neutral and I cannot find a spot where it won't, googled and found it may be control box problem, will try to see if it helps when I disconnect all linkages tomorrow...

few questions,
1) where do I connect to jump start the starter without connecting the battery and ignition keys
2) What is that corroded blue thing on the port side?
3) is the missing fuel hose connector on SB side supposed to be connected to fuel tank?
4) I think that is the throttle linkage that is disconnected on port side?
5) where could I find out where everything connects on the engine so I could confirm all the wires are connected to the right spot?

 

[racerone]

This motor is a corroded piece of junk.-----Worth 10 cents / lbs.-----Lots of better projects out there to restore.

 

[oldcab]

This motor is a corroded piece of junk.-----Worth 10 cents / lbs.-----Lots of better projects out there to restore.

would almost certainly fully agree, I wouldn't be taking it out to the sea, but if I could get it running half reliably, some kid may want a cheap engine to cruise around in the river or lake

 

[oldcab]

hi everybody, I need some help please...
just got this engine from a boat project
trying to work out if this will start

tried to do a compression test, but it's very hard to turn with the compression tester,
and I noticed the prop will always turn even in neutral and I cannot find a spot where it won't, googled and found it may be control box problem, will try to see if it helps when I disconnect all linkages tomorrow...

few questions,
1) where do I connect to jump start the starter without connecting the battery and ignition keys
2) What is that corroded blue thing on the port side?
3) is the missing fuel hose connector on SB side supposed to be connected to fuel tank?
4) I think that is the throttle linkage that is disconnected on port side?
5) where could I find out where everything connects on the engine so I could confirm all the wires are connected to the right spot?

found the service manual, all makes sense now

1) is the yellow cable
2) mercury tilt stop switch
3) that looks like the fuel pump, connects to fuel tank and fuel filter, strange to have to route the hose to there, maybe there was a hose missing
4) pretty sure this is throttle linkage
5) will need to trace everything

 

[Tassie 1]

Personally I'd take racerone's advice.
I think he knows a thing or two about outboard motors.
Not sure how much experience you have though.

 

[oldcab]

Personally I'd take racerone's advice.
I think he knows a thing or two about outboard motors.
Not sure how much experience you have though.

honestly I know f all, that's why I'm here hahaha

just took off the lower unit and it's shifting and spinning fine with minimal effort, but there's a small chunk of black thing near the water outlet which most likely was part of an impeller, will do the compression test tomorrow

but as I said if this engine could get up and running for minimal cost, someone will be happy to get a bargain when I put it on ebay for $1

in the meantime I'm looking for a low hours 4 stroke, but pretty hard to find with covid shortages

 

[The Force power]

honestly I know f all, that's why I'm here hahaha

just took off the lower unit and it's shifting and spinning fine with minimal effort, but there's a small chunk of black thing near the water outlet which most likely was part of an impeller, will do the compression test tomorrow

but as I said if this engine could get up and running for minimal cost, someone will be happy to get a bargain when I put it on ebay for $1

in the meantime I'm looking for a low hours 4 stroke, but pretty hard to find with covid shortages

I had two of these, there were not bad little engines except the water-jackets tend to weep-/leak

when cranking the engine in neutral it is normal for the prop to turn, due to oil in the gear-box (as long as the clutch is not engaged, easy to verify by holding the prop still while cranking)

First things to do;
- Get it to turn over with the starter and get the compression readings (if lower than 110 psi, Racerone's advice comes in affect)
- Drain/check the oil in the LU to see if its milky or gray (if gray, Raceone's advice comes in affect
(2) if your reverse lock works, the mercury switch is not really "necessary"
(3) Not hooked-up correctly, see attached diagram
(4) that is recirculation-hose, see attached diagram(to be repaired)

 

[racerone]

These motors ( 402 models ) had a history of the crankshaft breaking.-----I would not want one on my boat.

 

[The Force power]

These motors ( 402 models ) had a history of the crankshaft breaking.-----I would not want one on my boat.

question....I thought the later years were Yamahas blocks correct?

 

[racerone]

???----402 models are MERCURY !!

 

[oldcab]

I had two of these, there were not bad little engines except the water-jackets tend to weep-/leak

when cranking the engine in neutral it is normal for the prop to turn, due to oil in the gear-box (as long as the clutch is not engaged, easy to verify by holding the prop still while cranking)

First things to do;
- Get it to turn over with the starter and get the compression readings (if lower than 110 psi, Racerone's advice comes in affect)
- Drain/check the oil in the LU to see if its milky or gray (if gray, Raceone's advice comes in affect
(2) if your reverse lock works, the mercury switch is not really "necessary"
(3) Not hooked-up correctly, see attached diagram
(4) that is recirculation-hose, see attached diagram(to be repaired)

2) I thought the purpose of the mercury switch is when the engine tips over it cuts out engine? What's that got to do with reverse?
3) the diagram seems to agree the top goes to fuel filter and bottom to fuel lines of fuel tank?
4) I checked earlier and definately this is the linkage to the throttle on carby and is the part labelled #15,16,17,18,19 on page 30 "THROTTLE CONTROL LINKAGE AND SPARK ADVANCE"

 

[oldcab]

question....I thought the later years were Yamahas blocks correct?

I remember reading this somewhere too, don't remember where on top of my head

 

[racerone]

If reverse lock does NOT WORK the motor could tip up and over rev with prop out of the water.------Motor will not start ( no spark ) if operator has " ramp fever " and tries starting before checking if motor is in correct position !-----Find a better project motor.

 

[The Force power]

I had two of these, there were not bad little engines except the water-jackets tend to weep-/leak

when cranking the engine in neutral it is normal for the prop to turn, due to oil in the gear-box (as long as the clutch is not engaged, easy to verify by holding the prop still while cranking)

First things to do;
- Get it to turn over with the starter and get the compression readings (if lower than 110 psi, Racerone's advice comes in affect)
- Drain/check the oil in the LU to see if its milky or gray (if gray, Raceone's advice comes in affect
(2) if your reverse lock works, the mercury switch is not really "necessary"
(3) Not hooked-up correctly, see attached diagram
(4) that is recirculation-hose, see attached diagram(to be repaired)

Correction on #4 not recirculation hose! see diagram

 

[The Force power]

???----402 models are MERCURY !!

I thought the later blocks were made by Yamaha ?

 

[racerone]

The 402 models are MERCURY !!

 

[The Force power]

2) I thought the purpose of the mercury switch is when the engine tips over it cuts out engine? What's that got to do with reverse?
3) the diagram seems to agree the top goes to fuel filter and bottom to fuel lines of fuel tank?
4) I checked earlier and definately this is the linkage to the throttle on carby and is the part labelled #15,16,17,18,19 on page 30 "THROTTLE CONTROL LINKAGE AND SPARK ADVANCE"

It would be nice to have the serial# of the outboard so we would know exactly what unit we're talking about
(2) it has everything to do with in reverse because when the reverse-lock would not work the motor / LU will pop out of the water
(3) and is routed through the fuel-heater/pump
(4) Yes, you're correct

 

[The Force power]

The 402 models are MERCURY !!

okay

 

[racerone]

????-----What fuel heater are you talking about ??

 

[The Force power]

????-----What fuel heater are you talking about ??

sorry I meant pump, maybe I mixing them up with other pumps that pre-heated the fuel