Testing this weekend

[Dienewk]

Hi all

my original post was here http://forums.iboats.com/showthread.php?t=363668

and was related to the prop.

i am finally gettign to take the boat out this weekend adn wil lrun a few tests on it.

what should the boat idle at when just sitting? how to i get the Rpm measurment so i can work out for the correct prop (i do have a tacho now)

if it gets boggy like it does and starts to stall, someone said pump the bulb as i take off and see if it makes a diffrence anything else i should check while out there??

all help apreciated and i thankyou for your time.

Tim


EDIT:

my bad sorry for lack of info

1977 evinrude v4 2stroke, 14 foot crusader hull

and the tach has the setting for the 2 stroke.

THanks

 

[jay_merrill]

Re: Testing this weekend

I don't have complete info on your motor, so I can't give complete advice, but idle in neutral should probably be about 800 rpm.

I noticed in your other thread, that you bought a digital "Tiny Tach" for it. While that will work, make sure its the one for a 2-stroke engine, not a 4-stroke engine. If you bought the 4-stroke version, its going to read twice what your engine is operating at.

The correct tach for your motor would be one that operates off a signal from the rectifier on the motor. If you do a search on the word "tachometer" here in the forums, you will find many threads on what to buy and how to hook one up.



???

 

[Willyclay]

Re: Testing this weekend

if it gets boggy like it does and starts to stall, someone said pump the bulb as i take off and see if it makes a diffrence anything else i should check while out there??

Go back and read both of Steelspike's posts in your original thread. He also said to try activating the choke when the engine bogs down. If the RPM's jump, that will be a good indication that your carbs are gummed-up and need cleaning/rebuilding. On some motors, you can clean the main jets without removing them or the carbs. Good luck!

 

[Dienewk]

Re: Testing this weekend

Ok so i took the boat out today

she started easy and warmed up fine but was a bit bumpy when idling i took it out for a spin and at speed she went like a dream, brang her back to shore to see how it was idling and it was still a bit rough and the idle was up around 1500, i knew it was fairly high due to the stall issue i have when i take off and it bogs down.

i took it out for a spin to check the RPMs at speed the engine reved to about 5300rpm at around 65-75kms (not sure how accurate the speedos are.

stopped the boat to see how it would idle and it still stalled at idle.

the boat had to adults averaging 90kgs each and 2 kids about 40kg each


again a 1977 evinrude 115hp 14ft crusader hull.

if any more info needed let me know.

again all help apreciated with the bog down stall prob then i can look at the correct prop

 

[kenmyfam]

Re: Testing this weekend

Just going back to your other thread in the link and to confirm a few things for the others.
I am not clear on a couple of things.
Have the carb's / fuel system been serviced ??
Did you try popping the choke / primer and / or squeezing the bulb ??
Have you done a link n sync ??
Did you find the root cause of dropping a cylinder ??

My concern is that if the root cause is not found and corrected you could drop a cylinder again in a short space of time.

 

[Dienewk]

Re: Testing this weekend

Just going back to your other thread in the link and to confirm a few things for the others.
I am not clear on a couple of things.
Have the carb's / fuel system been serviced ??
Did you try popping the choke / primer and / or squeezing the bulb ??
Have you done a link n sync ??
Did you find the root cause of dropping a cylinder ??

My concern is that if the root cause is not found and corrected you could drop a cylinder again in a short space of time.

carbs where link and sync with the rebuild but wherent serviced (rebuilt)
tried the choke it stalled out
tried squeezing the fuel bulb but it was already hard

now you have me worrried the dropped cylinder i am unsure of, i thought it was more of an age thing and it had just done its time.

 

[steelespike]

Re: Testing this weekend

Normal idle is about 700.Hard to believe it could stall at 1,500.
Shifting at that rpm would be an adventure.If shifting seems almost normal
then rpm may actually around 700 or so.
You might pull and check the plugs for fouled/wet. Exceptionly clean?

 

[kenmyfam]

Re: Testing this weekend

Agree, how do the plugs look ???

 

[Dhadley]

Re: Testing this weekend

Just something to keep in mind while you're running with clogged carbs - if a cylinder isn't getting fuel, it's not getting oil either. Pistons don't like that.

 

[Dienewk]

Re: Testing this weekend

http://i461.photobucket.com/albums/qq332/dienewk/plugs.jpg


here is a pic of the plugs that came out of her after yesterdays run.

hope they help


Oh dont mind the date on the picture its my sons camera (he is 6 and a budding photographer)


if they arent close enough or clear enough i can take some more he has just told me how to use the camera lol

 

[Dienewk]

Re: Testing this weekend

there is a bit of grit around the outside of the plug but the spark part itself is a greyishlight brown.

 

[emdsapmgr]

Re: Testing this weekend

Steelspike is correct. The engine should idle between 650 and 750 in gear when the boat is idling at normal floating level in the water. If you have poor idling at that rpm-or it won't idle at that rpm (only higher) , you may have crud/debris in the carb idle circuits, which will affect idling characteristics. Dried fuel can clog these idle fuel passages. Only way to clean them is to disassemble and clean all passages out with an aerosol carb cleaner. If it only idles at 1500, you may have fuel from the mid jets providing fuel, if the low speed jets are not working. Sound like you are getting good rpms at full throttle, though you may have a little too much pitch on the prop-your top end rpm's are a little low.

 

[Dienewk]

Re: Testing this weekend

Steelspike is correct. The engine should idle between 650 and 750 in gear when the boat is idling at normal floating level in the water. If you have poor idling at that rpm-or it won't idle at that rpm (only higher) , you may have crud/debris in the carb idle circuits, which will affect idling characteristics. Dried fuel can clog these idle fuel passages. Only way to clean them is to disassemble and clean all passages out with an aerosol carb cleaner. If it only idles at 1500, you may have fuel from the mid jets providing fuel, if the low speed jets are not working. Sound like you are getting good rpms at full throttle, though you may have a little too much pitch on the prop-your top end rpm's are a little low.

Decided i am not mechanical enough to do the carbs so i will put them into a mechanic to get them done (just need to fina a good one of those) i look forward to posting a end to this prob i have.

i was also told the prop on the boat should be ok but i should ventilate it by drilling a hole in each of the 3 blades on the prop, the suggestion came from a prop shop here in oz, the guy is sendign me a pic of how to do it, any comments on that?

 

[kenmyfam]

Re: Testing this weekend

Don't know about drilling the blades ??? but I drilled the hub in my larger pitch prop in 3 places. It is only good for hole shot though from what I experienced. It did however make a huge difference with that. I also went a stage further and machined some of the "cup" off the blades. Result is 5,800 rpm at WOT and a great hole shot. But the WOT rpm was unchanged just by drilling it.
I will dig up the print on the drilling and post it unless someone else beats me to it.

 

[kenmyfam]

Re: Testing this weekend

Here is a print with some base dimensions. You will most likely get better advice in the prop section if this is the path you wish to follow. Personally I would get the motor running at it's peak efficiency before doing any prop modifications. I consider that to be "fine tuning" when everything else is in order.
Still worried about you losing a cylinder again.
Edit,
I know it looks like nothing is attached, just click on the left hand side of the box.

 

[Dienewk]

Re: Testing this weekend

Here is a print with some base dimensions. You will most likely get better advice in the prop section if this is the path you wish to follow. Personally I would get the motor running at it's peak efficiency before doing any prop modifications. I consider that to be "fine tuning" when everything else is in order.
Still worried about you losing a cylinder again.
Edit,
I know it looks like nothing is attached, just click on the left hand side of the box.

it did seem like i was jumping the gun Kenmyfam, but i WONT be touching the prop or anything else till i work out this stalling/idling problem. thanks for your posts and i will get back to you all when i have a result (good or bad)

cheers

Tim

 

[kenmyfam]

Re: Testing this weekend

Good Luck and post back with any further news.

 

[Dienewk]

Re: Testing this weekend

ok got the carbys cleaned reset and linked and synced.

took her out and she started well and idled well ran well for a bit but still was stalling out of the hole, on the ocasion i would sit there idling waiting for the kids to get back on the tubes then hit it once they where ready and she would stall or i would pull them steady on the knee boards while they where getting up, then hit it to take off and stall.

so will call the mechanic on monday and drop it back to him but it still has me baffled why it is still stalling , he said he may have to drill out the low speed jet? ( ithink thats what he said) but that can also give them too much fuel.

so i guess i will leave it in his hands, but i am still interested to hear any suggestions.

Tim

 

[Willyclay]

Re: Testing this weekend

As I understand it, this is a 1977 Evinrude 115HP 2-stroke motor that had some unknown number of previous owners. Last summer it ran great until it lost one cylinder and was rebuilt but the carbs were not touched at that time.. After the rebuild, it ran okay on the first tank of fuel but then became sluggish and bogs. Recently after a professional cleaning/rebuild of the carburetors, it starts, idles and generally runs better but still bogs during acceleration. Based on this, I have some questions for you.

1. Is the mechanic who rebuilt your carburetors the same person who rebuilt your motor?

2. Did the person who rebuilt your motor provide any sort of explanation, findings or cause for the loss of one cylinder? If so, what was it and what corrective action was taken?

3. Why does the mechanic want to modify/enlarge the low speed/idle jets when the motor ran well without those modifications prior to the loss of one cylinder and rebuild?

4. Has anyone taken compression readings recently? If so, what are they?

The experts on this forum, which I am not, are really great at solving problems and helping us fix problems but they need good information from the owner. I know they can help you, so hang in there and provide as much info as you can. Good luck!

 

[Dhadley]

Re: Testing this weekend

If you have a "mechanic" who wants to drill jets, you need a new mechanic.