cant get to idle

[coolguy147]

1961 mercury 500 50hp

well carbs are clean. good spark sure of. 128-135 compression last time i checked. needles 1 5/8 out both low speed. its fluctuates all the time. slowly dies. takes choke to start when warm. what to do!

 

[corm]

Re: cant get to idle

Hi,

It seem like you idle needles are out a little far. If I remember they used to run about 7/8 to 1 1/8 th turn out. So you could have a vacuum leak in the crankcase or a leaking crankshaft seal. Check the oil recirculating hose out too. I would make sure the points are set right first.

 

[coolguy147]

Re: cant get to idle

to further describe the problem ill set the idle at one speed it will idle good. then stall then ill restart with choke. idle down and it wont be the same and stall

also at idle my tele tale just like drips along the side of the midsection. and the engine gets kinda hot. but i have a new impeller in it. but i have to say when restinstalling the impeller i acidently tore a very small piece out of one of the fins and on the very outside top of the impeller

new oil line by the way

wont run with 1 turn out needles i here its 1 turn out but just wont run at slow speed. the motor kinda bogs down sometimes when i try to rev it up.

when i rev the motor quick and bring it back down it pops 1once or twice. sometimes it will pop and just kills it self at low speeds

points im sure i set them within specs. tell how to set them so i can reference there a little different then omc's

is it hard or expensive to replace these seals?

 

[coolguy147]

Re: cant get to idle

oh yeah and im running 24:1 or richer oil mix

 

[j_martin]

Re: cant get to idle

to further describe the problem ill set the idle at one speed it will idle good. then stall then ill restart with choke. idle down and it wont be the same and stall

also at idle my tele tale just like drips along the side of the midsection. and the engine gets kinda hot. but i have a new impeller in it. but i have to say when restinstalling the impeller i acidently tore a very small piece out of one of the fins and on the very outside top of the impeller

new oil line by the way

wont run with 1 turn out needles i here its 1 turn out but just wont run at slow speed. the motor kinda bogs down sometimes when i try to rev it up.

when i rev the motor quick and bring it back down it pops 1once or twice. sometimes it will pop and just kills it self at low speeds

points im sure i set them within specs. tell how to set them so i can reference there a little different then omc's

is it hard or expensive to replace these seals?

Scratches in the end plate will bypass enough water to make a pump fail.

1. You're overheating. Fix the pump. You wrecked the impeller, and check the bottom plate and housing real good this time.

2. Popping usually indicates it's a little lean. With the overheat, mix is a wild variable, so fix the cooling first.

BTW. overly rich oil mixture will cause it to run lean. Because the oil is sensitive to temperature, it would be expected to cause wide variation in mixture. Don't do it, mix it 50:1 like it's supposed to be.

This is a classic case if iatrogenic (doctor caused) disease.

hope it helps
John

 

[coolguy147]

Re: cant get to idle

i dont know man im stillling not buying the 50-1 mix people are saying.

no its not overheating. again like i said before i rev it up and it will cool off nothing hurt.

end plate? huh. you mean the plate you stick on right on top of the impeller. well it was just so darn hard to stick the impeller in there and yet get it out i bend it so much there a little piece tore out.

 

[coolguy147]

Re: cant get to idle

bump

 

[j_martin]

Re: cant get to idle

i dont know man im stillling not buying the 50-1 mix people are saying.

no its not overheating. again like i said before i rev it up and it will cool off nothing hurt.

end plate? huh. you mean the plate you stick on right on top of the impeller. well it was just so darn hard to stick the impeller in there and yet get it out i bend it so much there a little piece tore out.

1. I guess the engine manufacturer doesn't know anything about it.

2. It's overheating at idle, by your own description, which is when you are having trouble.

3. If you damaged the impeller not knowing how to lube it up and roll it in, which anybody can do and is described in detail in the manual, you might have damaged other parts in the pump.

If yer in over your head, which is apparent, find some help.

John

 

[corm]

Re: cant get to idle

Hi,

If you have a dwell meter hook it up to the points when it is running. Set it on 4 lobe cam and it should be 48 degrees if the points are set right. You can set them at .007 - .008 on the high spot of the lobe. Lube the cam lightly so the point follower does not wear down right away.

Gap the spark plugs (J6JC) at .025.

Merc had a Service Bulletin on the oil mix for these engines back in the late 60's or early 70's. Run it at 50-1 or bring 4 sets of plugs in the boat with you. You will need them. Hopefully not all in the same day.

If the engine is running warm at an idle it will be impossible to set the idle or get it to idle with any consistency. The engine will pop because the internal temp is to high not allowing the fuel charge to enter the chamber or you have a crankcase leak. The timing pickup can cause this but most people can not figure out how to mess it up so it is usually set ok.

If after fixing the above you need to replace a seal it is fairly easy and I do not know what they cost these days. They used to be $11 ea

 

[coolguy147]

Re: cant get to idle

what seal? it didnt overheat! omg

plugs already set. fine illl mix 50-1. ill put the leftover gas on my 10hp.

i used to have a dwell meter. but took it back because the tachometer didnt work on my engine. and i couldnt figure out how to work the temp guage.

alright ill get the impeller replaced 10 bucks not that bad i guess.

im not sure that i want to take my plugs out again cause my third plug was stripped and had to put the helicoil in. i did it properly and stuff but you know i dont wanna keep taking it in and out giving it stress

 

[coolguy147]

Re: cant get to idle

ok heres my plan to steps to make my motor better running

replace impeller
replace spark plug wires
set needles at 1 turn out
take magneto apart again set points at .008-.010
clean and reset points
lube cam very very very light oil

i want to check max advance but i dont have timing guage. have a timing light somewhere i seen it before

then next step after if not improved to check syncing the carbs with magneto

geeze the more and more i learn and read the more it becomes complicated and i thought i had this down

 

[coolguy147]

Re: cant get to idle

Hi,

If you have a dwell meter hook it up to the points when it is running. Set it on 4 lobe cam and it should be 48 degrees if the points are set right. You can set them at .007 - .008 on the high spot of the lobe. Lube the cam lightly so the point follower does not wear down right away.

Gap the spark plugs (J6JC) at .025.

Merc had a Service Bulletin on the oil mix for these engines back in the late 60's or early 70's. Run it at 50-1 or bring 4 sets of plugs in the boat with you. You will need them. Hopefully not all in the same day.

If the engine is running warm at an idle it will be impossible to set the idle or get it to idle with any consistency. The engine will pop because the internal temp is to high not allowing the fuel charge to enter the chamber or you have a crankcase leak. The timing pickup can cause this but most people can not figure out how to mess it up so it is usually set ok.

If after fixing the above you need to replace a seal it is fairly easy and I do not know what they cost these days. They used to be $11 ea

i thought this motor was .008-.010 setting for the points? not .007?

 

[corm]

Re: cant get to idle

i thought this motor was .008-.010 setting for the points? not .007?

Caught me! Your correct. .008-.010 is what you want.

 

["G"]

Re: cant get to idle

These engines will run when all the components are in good shape and correctly adjusted. And of course... good compression. Do yourself a favor- BUY A MANUAL and follow the directions for service. Listen to what the guys in this forum tell you, weigh the info and see for yourself, we are trying to help you. There must be an understanding of general mechanics or this info will do no good. Here's my suggestions:

#1, Check your compression and record the findings. Look for variances of greater than 10%.
#2, open the magneto and adjust the point tension, gap and dwell angle to correct spec. Be sure to clean the rotor cap well and replace any cracked parts.
#3, follow the manual and adjust the carburetor to ignition timing both primary and secondary. This synchronizes the timing with the fuel. Idle screws should be out 1-1 1/2 turns to start. Assure gaskets are tight and not leaking air or fuel.
#4 If the WP impeller, housing or plates needs work then replace them but a bad WP is going to cause/cost you big trouble.
#5, think back into your history of owning this engine. Was it ever overheated where you couldn't put your hand on the motor? That's important because the pegs that hold the reed blocks in place are plastic. Once overheated, they melt now they're going to be a problem holding the reeds in place as they vibrate. That may be your problem as I read your posts. If you're seeing gas spit back out the carbs when running that is a good indication of a reed problem.
#6, use a good 50-1 tcw rated outboard oil. 25-1 is for older 2 stroke engines when they used 30wt motor oil. New technology, better oils, better protection.
#7, make your final adjustments in the water. Setting it all up can be done on the muffs.

Good luck.

 

[coolguy147]

Re: cant get to idle

i guess you dont know my older threads lol its alright

128-135 compression already before i started restoring it.

no gas spitting back. i didnt know that was because of reeds? neat learn a new thing everyday

i know its 1 1/2 out but thats pretty general

yes ill replace the impeller might even purchase it from iboats.com the water pump is a bowl in the the lower unit with a wear plate and screw on cover on top. very very different from other engines if you dont know. but its perfectly fine next time ill remember to grease my impeller first

nah ill stick with 24:1 for now. its the same as if im breaking in the motor for the first time.

my magneto is like in perfect condition. new coil. points ok condition. will take apart and re-adjust points and light oil then maybe get a multi meter with a dwell feature