I looked and looked but found nothing

[crzy4wlvs]

I have been tring to find the right ratio for my 1979 100 hp johnson outboard, i have been using 50:1 but when i start my motor it blows out alot of smoke till it warms up! shold this be a mixture problem or is there something else that i should look for?........I looked at past posts for ratios but it seams like i have the oldest motor around.<br /> Also I baught this 2 and four cycle fuel cleaner to try and clean the fuel system alittle was this a bad idea?<br /> Oh, And one more question, how do i tell what pitch my prop is? <br /> Does any one recomend any specific 2 cycle oil? i have been using penxoil reg. 2 cycle.<br /> <br />-----------------------------<br />"one who does not ask, shall not recieve"

 

[Dhadley]

Re: I looked and looked but found nothing

50:1 is correct and Pennzoil Marine oil is a good oil. You might want to try the Pennzoil blend (partial synthetic).<br /><br />What spark plugs are you using? (Please be specific)<br /><br />Good luck!

 

[crzy4wlvs]

Re: I looked and looked but found nothing

sorry dhadly i thought that i was being specific.<br />I am using 4 champion 821- l77jc4. Do you think that this might be my problem? maybe the gap isnt set right? Is this what is causing all the smoke?<br />thanks agian!

 

[iRich]

Re: I looked and looked but found nothing

Your prop should have some numbers stamped on it. If you post them here someone I'm sure will tell you the pitch.<br />Rich

 

[NathanY]

Re: I looked and looked but found nothing

i have been using 50:1 but when i start my motor it blows out alot of smoke till it warms up!

That is pretty normal, it is just running a little rich when cold.

 

[crzy4wlvs]

Re: I looked and looked but found nothing

when i went outside to look at the #'s that were stamped on the prop it looked like it said 7373 but wast really sure it has been repiared then pianted so i think that those are the right #'s. if these are the wrong #'s is there another way to find out the pitch, The only reason why i am looking for the pitch of the prop is so that i can fix this problem that i am having, <br /><br />When i have the boat in full throttle I get more rpm's then i do speed. Am i right? if i want more speed with my rpm's i need to change the prop?

 

[iRich]

Re: I looked and looked but found nothing

crzy4, go here: http://www.marinedepo.com/proschool101.html <br />to get a basic understanding of how pitch affects<br />thr rpm's. You really need to know what your rpm's are though.<br />btw, more smoke at start up is normal.<br />Rich

 

[crzy4wlvs]

Re: I looked and looked but found nothing

thanks rich,<br /> I took a look at the web site that you gave me and understand now.( i think) less RPM's bigger prop, more rpm's lower prop, there really isnt a way for me to find out the pitch on the one that i have now that now that i cant read the #'s? well i will have to get orig. manual to see what the recomended pitch was im sure its probly the same thing

 

[Solittle]

Re: I looked and looked but found nothing

Before you go nuts with props you need to find out what your rpm is at wide open throttle. That will tell you if the prop you have is the right pitch or if you need to go up or down. Any prop shop or full service dealer should be able to tell you the specs of the prop you have.<br /><br />All older 2 cycles smoke a lot until warm. Yours is a good motor and with care you should get a lot of use out of it. If it were mine I would use only OMC, Merc, or Yammy oil. I have run "off brand" oils and have not been satisfied.

 

[crzy4wlvs]

Re: I looked and looked but found nothing

thanks solittle, <br /> I will try those brands of oil, your right the motor does run great it's just that smoke that is really embarassing when i go to the boat launch with all of those really expensive boats, and i blow lots of smoke.

 

[Spidybot]

Re: I looked and looked but found nothing

If you visit a prop selector (here's Merc's) you can get an idea of the theoretical pitch. Compare this to the rpm you have at WOT. It is important the you respect the recommended rpm range (4500-5500 for your motor). Your gear range is 2:1 which you need if you wanna calculate the pitch yourself (spreadsheet available here )