Logo
FULL SITE MENU

Mercury 40 hp 2cyl 2stroke No lock on reverse

J

jp_banks

Member
My engine tends to raise out o

My engine tends to raise out of the water on reverse. I do not have a trim and tilt system. What could cause this problem. Thank you.

JP
 
"provided the linkage hasn&#39

"provided the linkage hasn't been messed with and moves freely, someone probably clocked the cam on the shift shaft when they changed the water pump. Quite embarrassing at the boat ramp trying to back of the trailer
blush.gif
"
 
Thank you for your response. I

Thank you for your response. I don't understand the term "Clocked the cam". Are you saying they put it at the wrong position. How hard is this to correct. Thank you.

JP
 
It's a 1982. Thank you for

It's a 1982. Thank you for your indepth explanation. It is very possible someone put it back together wrong. This is the engine that I ask questions about concerning fast idling. I found the turnbuckle on the trigger mechanism installed backwards and I was not able to get the idle down until I turned it around. I guess I'll have to take the lower unit off and see if I can correct it. Because even at low idling speeds the engine tends to raise out of the water. Is there any special thing I should look out for or be aware of. Thank you.

JP
 
"If the turnbuckle was upside

"If the turnbuckle was upside down the timing is now completly off. The trigger rotates around the flywheel to control timing. I suggest a factory manual and due the link and sync. There is also a base point for control cable installation.
The engine should lock down in neutral and rev. If the engine is not locked and is in neutral, the lower unit needs to come off. Then simply slide the cam up off the shaft and turn it.
When dropping the lower unit do it in nutral, 2 5/8 nuts up front, remove trim tab 7/16, remove 2 nuts under trim tab 9/16 I think. The cam should be positioned so the rod is half way up the slope in nuetral. Re-install lower, verify control and lower is still in nuetral by spinning prop. Wiggle flywheel to align splines. Change the water pump while you have lower off. I can help with more tomorrow"
 
I'll try dropping the lowe

I'll try dropping the lower unit tomorrow. I'm hoping after removing the bolts/nuts that you're referring to the unit will come off easy. I have never pulled a lower unit before. I'll let you know how everything turns out and thanks again for all your advice.
JP
 
"Hey JB <[img]"http://www.mari

"Hey JB
lol.gif
you know your peas and boat engines. You hit the problem dead center. Of course it took me several tries to get it right but I got it. It didn't pose as much of a problem as I thought it would. You sure have helped my out here and I do appreciate it very, very much. Have a great day.
JP"
 
"Do the waterpump now that you

"Do the waterpump now that you know how to get the lower off. The impeller is less than $20, you can buy it here if you want. Remove lower, undue 3 7/16 nuts on plastic housing and remove. Slide off old, install new impeller on key, lube with vasoline, slide housing down on top impeller while turning drive shaft clockwise, re-assemble.
When you need help with the link and sync, just ask. The base timing is 3 degrees + or- 1. Don't mess with the stops on the exhaust plate, they are set at the factory. Open throttle all the way and look down carb, it should be fully open if things are set right. Also when in gear at idle the rubber stop should just be a hair off of carb pick-up shoe. Keep an eye on starter bolts they get loose and break the engine casting. 2 drops of oil on starter bendix to help gear engage. Good job on rev lock, rookie."
 
"Now, I would like to talk abo

"Now, I would like to talk about the timing. When I turn the trigger arm around and slowed the idling down, I took it out on the lake and it ran great. It had good speed and did not hesitate. So my question is: should I mess with the timing. Thanks.

JP"
 
"I can't imagine how the t

"I can't imagine how the trigger rod end got messed with, but lets start here. At idle, in gear, the timing should be 3 or so degrees. It cost nothing to check it. If its not close to that then the high rpm is going to be off. Anything more than 27 degrees at WOT and it will detonate, causing problems. Check the low rpm timing and lets see. Timing light to top plug."
 
"Ok JB, I acquired myself a ti

"Ok JB, I acquired myself a timing light and here is what I have. When I first start the engine at idle, the mark on the flywheel shows 9 degrees under the pointer. When I shift into forward gear at the same speed the mark on the flywheen moves to the left approximately 4 dots. I don't have a tachometer so I don't know at what speed the engine is runing. If you will send me your email address I can email you a picture of the marks on the flywheel and maybe you can interpret what is happening. I tried to send it here but it was more than 100kbytes. Thanks.

JP"
 
"click on my name, 9 degrees i

"click on my name, 9 degrees is to high, will try to gather the link and sync during lunch break, if you have a fax I could send easier"
 
"JB,

I just want to thank

"JB,

I just want to thank you for all your professional help. Thank you for your patience and perseverance. Most people would have thrown up their hands in disguss but you hung in there and help me through to the end. I really do appreciate you. Hope all your days are filled with goodness.

JP"
 
Back
Top