Evinrude prop way to small??

[82rude]

Re: Evinrude prop way to small??

do a decarb before you go any further and then recheck comp numbers.id also take the front carb cover off and advance the throttle (not running)and verify that the carbs are opening all the way.as steelspike said carbs may need to be redone .also wheather you think their new or not make sure you have new and correct sparkplugs installed.you might want to also verify that the coils are not failing under load,though some may disagree im telling you from experience that coils dont like hairline cracks period.

 

[glenn property of pam]

Re: Evinrude prop way to small??

i have a 70hp in the yard of the same vintage that was playing up and would not rev out on the water it turned out to be the butterflys were not opening fully due to a loose screw in the controller. the other thing i leant about the 70 is the pin that holds the butterfly likes to hit the carb bolt on the other side of the linkage which can stop the carbs opening or closing fully which can lead people to mess up the link and sync. add your location in case anyone is close by that can meet up with you and hear the motor run or get a video of the motor running with sound and post it on youtube as the noise it makes is a good clue of what its doing

 

[steelespike]

Re: Evinrude prop way to small??

"decarb" some times 2 stroke outboards get a buildup of carbon that makes the rings stick.
Get some "Seafoam"follow the directions on the container for decarb. There have been many successes
improving compression.You will still have be sure about other things we have discussed.

 

[82rude]

Re: Evinrude prop way to small??

"decarb" some times 2 stroke outboards get a buildup of carbon that makes the rings stick.
Get some "Seafoam"follow the directions on the container for decarb. There have been many successes
improving compression.You will still have be sure about other things we have discussed.

thanks ,i forgot that the orginal poster was new to outboards.

 

[Chris1956]

Re: Evinrude prop way to small??

Compression in the 90s and low 100s is fine. With the motor and cowling off, advance the throttle all the way and see if the carbs open all the way. Remove the spark plugs, reinstall them into the plug wires and ground the bases to the block. Put a timing light on the top spark plug and crank the motor and check the WOT timing. A service manual will tell you if it is correct. If that checks out, you may be overpropped. See if you can borrow a prop with 13" pitch and retest.

Oh yes, post any potential motor problems in the Johnson/Evinrude motor forums, as those guys are experts.

 

[82rude]

Re: Evinrude prop way to small??

chris i would think even if your way over proped you,d still get rpm,s you just wouldnt get anywheres to a certian degree.i would also test the prop for clutch slippage while were at it.what kind of bracket was built and how high?scratch the prop slippage theory it doesnt make sence either in this case.ive amended this post a little as in order to get the rpms the o.p. has stated i would think he,s have to be grossly overproped not just a 17p which all things being equal should be within the capabilitys of a 70 hp motor though for heavy boats id think a 15 maybe?but i also agree he,d be better served over in the johnson and evinrude forum .

 

[Unruh]

Re: Evinrude prop way to small??

Ok thanks the butterflys open to straight horizontal I assume this is all the way?

 

[82rude]

Re: Evinrude prop way to small??

correct.has this motor been like this from the day you got it or did it just start acting up later?what type of plugs are you using ,might seen like a silly question but many a ill running omc has been made right by putting in the correct champion spark plugs.take the advise of the guys here ,spark, commpression and fuel ,all 3 are needed to run .for a couple of bucks id try3 new plugs and go from there not forgetting to decarb the motor also ,it might bring up those comp numbers.if you got muffs nightime is a good time to test run also as you can check for any spark leakage(just a thought).its amazing what will show up in the dark .comp?fuel flow?good strong spark?get a good manual and read up on your motor and the theory of 2 stoke operation it can be a little dull but also answers a lot of questions.also make sure carbs are clean and not plugged .im sure this has been covered all ready but once more wont hurt.

 

[glenn property of pam]

Re: Evinrude prop way to small??

your motor requires compression spark and fuel to run correctly. compression is low but that might be the gauge as you can test with another and get diffrent numbers plus you tested cold so thats not a good reading anyway the diffrence is high but with in range and it runs so thats proberly ok. you tested spark (the people who post here know there stuff so its a good idea to follow them when they ask you to test something. you can buy a spark tester cheap and test the spark lenth or make one but that test needs to be done to assist the people helping you). knowing the motor you have it sounds like its fuel related which can be a air leak or a plugged carb. we need to know if the carbs have been cleaned, does the fuel bulb stay firm when pumped, any leaks around the carbs, have you drained the carbs to see if you have water in the bowls (remove bottom brass screw that you can see after you remove the air cover), if you pump the bulb while trying to gain speed on the water does the motor rev up, is the red choke lever in the right direction. we all want to see you happy on the water so please help us help you. we like pictures, video's and ans to questions we ask

 

[82rude]

Re: Evinrude prop way to small??

also get a mod to move this over to j/e motor section and you will have the boys all over this like a kid on smarties.

 

[Unruh]

Re: Evinrude prop way to small??

had NGK B7HS plugs local auto parts store sold me Autolite 4093 to replace didnt help. Motor has ran like this since i bought it, have taken it out several times and never gotten above 2500 rpm except twice for maybe 15sec. choke lever correct, primer bulb stays tight, pumping while running on lake doesnt help, spark jumps half inch. the bracket to raise the motor is made from 4 in X 1/4 angle iron cavitation plate is 2 in above bottom of boat can adjust down if too high. havnt done anything with the carbs yet beyond removing the air cover. i believe i removed the correct screw- no water, just fuel in the bowls.

there is an air bubble in the fuel filter- would that cause my problem?

i bought some Seafoam to run through. after that- carburator? where can i find step by step instructions?- want to learn but dont know much yet

 

[Unruh]

Re: Evinrude prop way to small??

just saw your last post there 82rude how do i get it moved? im fixing to get real busy at work for the next month so might have to become a winter project would it be better to start a new thread in j/e then?

 

[82rude]

Re: Evinrude prop way to small??

if a mod doesnt see this and move it yes id start a new thread just mention that you had it here also .though i personally think the motor is too high thats not the main issue, you got no rpms thus lack of fuel or a coil or plug is failing.ive only got 35 years fooling around with j/e though yours is a little new for my dealings (50,s and 60,s for me )im way better doing than talking i always have a hard time getting across what i want to do on line ,too bad you wernt down the road id look at it and figure it out alot faster than my babbling on here takes,lol.theres guy over there in the j/e section a lot better on line than i will ever be. 35 years is rookie status for some of them

 

[glenn property of pam]

Re: Evinrude prop way to small??

watch a few youtube videos on rebuilding the carbs on a evinrude 70. you will need 3 carb rebuild kits the carbs have 2 ways the fuel flows. the first is the low speed jet the second is the high speed jet if you have 1 or 2 carbs with blocked/blocking high speed jets the motor will stave for fuel and will not rev. they also have videos on seafoam it gets real smoky when you use seafoam so better not to do it in the middle of town.

 

[Unruh]

Re: Evinrude prop way to small??

ok thanks I'll try the seafoam and carbs after corn harvest is over then go from there thanks for all the help!

 

[Unruh]

Re: Evinrude prop way to small??

FYI- Seafoam fixed it! 33mph @ 5400 rpm now.... Thanks all for the advice!

 

[Radarman68]

Re: Evinrude prop way to small??

Thank you for coming back and letting all us lurkers know what the problem was! Glad to hear you are back in business, enjoy!