Mercury 402 40hp two or four strock?

[icon07]

Hi everyone. i just bought a 14' olympic boat with a mercury 402 40hp. the owner toll me that it is for strock but my friend said it is 2 strock. could you let me know how to check if it is two strock or four strock? it has serial #4576044. the owner said it has not in the water since 1985. it worked that time. so could you show me what do i need to do before i start the engine?
thank you very much.

 

[Barnacle_Bill]

Re: Mercury 402 40hp two or four strock?

It is a 2 stroke (cycle) motor. I highly recommend you read this: http://forums.iboats.com/showthread.php?t=158086

Also it is a 1977 model and the gas/oil mixture should be 50:1

 

[icon07]

Re: Mercury 402 40hp two or four strock?

that was quick. thank you very much for your help.

 

[DutchMerc]

Re: Mercury 402 40hp two or four strock?

It is a 40HP2Stroke, and i have the same engine. I bought it under the same conditions, hasn't ran for more then 15 years... This summer i startet using it after some necesary repairs and maintenance. The link in the previous post also helped me to get it back alive, and i took it out this summer and it ran fantastic. Make sure the lower-unit is O.K. and the oil is up to date...Replace at least the impellor, and check if you have sufficient waterpressure before you take it out. Have fun...

 

[icon07]

Re: Mercury 402 40hp two or four strock?

Just a quick update. I changed lower unit oil, replaced spark plug, put oil into spark plug, turned the flywheel few times. next day i came out started the engine 4 times it ran really good.

 

[Barnacle_Bill]

Re: Mercury 402 40hp two or four strock?

You should still change the impeller. They dry rot from sitting so long.

 

[icon07]

Re: Mercury 402 40hp two or four strock?

Hi Bill. you are right. engine ran for few second. i noted that no water came out of pee holes.i stopped it right away.just bought impellor today i will try to replace it this weekend. i have the clymer repair manual. but still not feel comfortable to do it. if you have idear that would help me alot.
thank you

 

[DutchMerc]

Re: Mercury 402 40hp two or four strock?

Put the gears in neutral, unbold the lower unit, and carefully take it apart. Make sure you notice the position of the cam on the gearshaft, this will lock your motor down when in reverse. After cleaning and replacing the impellor, grease up the spline from the gearshaft, put the cam back in the correct position, make sure the rubber joint from the exhaust and the watertube are in position (some grease might help) and slide everything back together. Check if the propellor is free in neutral, locked in one direction in forward, and locked in both directions when in reverse. Put the tail in the water, crank it up and check the pee-hole. Have fun

 

[icon07]

Re: Mercury 402 40hp two or four strock?

Hi everyone. I have a problem with remove lower unit.
followed instruction of my clymer manual i removed trim tab bolt, trim tab recess bolt. remove the nut from the bottom of the anti-cavitation plate. 2 nuts each side of the gear housing. i pull the lower unit out haft way but look like it catch something. and didn't want to come out. did i miss any nut up there? please help.