FIRST Time on the lake! Few Hic-Ups!

[Sander]

Hello guys,

So after a few weeks of working on the boat, today we finally took her out to the local lake.

Being a first timer for backing up a trailer and releasing the boat, things went quite smoothly. She started up and we were on our way. During the first 40min of the ride everything was good, the motor sounded great with no hiccups. Taking it gently we drifted in the waves at slow speed, I opened her up close to full throttle for a few minutes, than we stopped for a swim. Turned the boat off.

After about 30min of swimming it was time to go. However, the motor did not start. Tried numerous times, but it just would not turn over. After a little panic and good 20 min, somehow she started, but while in idle/slow speed she would bog, pretty bad, and if I took off all the throttle she would die. Once I would opened the throttle just a bit, it ran with no problem.

With some hard effort we managed to get her back to the ramp. The motor is a 1971 Evinrude 100HP. I suspect my slow speed needle is the cause of the problem, what do you guys think? Why did she ran perfect when we first put her in water, and than like this right after opening throttle almost full and stopping for a swim with the motor off?

I am 99% certain it a fuel problem. I would like and would much appreciate to hear your comments/thoughts.

Thanks.

 

[Daviet]

Re: FIRST Time on the lake! Few Hic-Ups!

Have you overhauled the carbs? Sounds like you have some problems in the idle circuts in the carbs.

 

[freddyray21]

Re: FIRST Time on the lake! Few Hic-Ups!

does sound like carb, but may be timing link. check and make sure nothing came loose in the carb linkage.

 

[Sander]

Re: FIRST Time on the lake! Few Hic-Ups!

We have not done anything to the carburetor, it only bogs on slow speed and dies on idle. Could it be a fuel filter? To me everything points at the slow speed needle. If I change it might as well re-build the carbs, yeah?

 

[1946Zephyr]

Re: FIRST Time on the lake! Few Hic-Ups!

I would check the needle adjustments on the low speed needle. They could be off a little. Fuel pump could possibly be getting week.

 

[Sander]

Re: FIRST Time on the lake! Few Hic-Ups!

Will perform a few test this week, I hope it will be something I can fix myself.

 

[Daviet]

Re: FIRST Time on the lake! Few Hic-Ups!

Let us know what you find.

 

[Kaplooi]

Re: FIRST Time on the lake! Few Hic-Ups!

You need to open up the carb and check the idle circuits for blockage. The fuel passages are usually very small and can be plugged up by even a tiny bit of dirt or sand so you may need a sewing needle or compressed air to blow them out if they're completely plugged. I had a Johnson 8 horse with a plugged solid idle circuit once, and it didn't idle or start for crap but ran normal at mid to high throttle because the main jets were fine.

 

[Sander]

Re: FIRST Time on the lake! Few Hic-Ups!

Thanks, Daviet! Will get back with results sir.

Kaplooi, good information, thanks. I am little afraid to dissemble the carb as I have never done it before, perhaps it is not as hard as I think, but I am sure it will be a challenge for me.

 

[BonairII]

Re: FIRST Time on the lake! Few Hic-Ups!

Film yourself(or take pics) of you taking it apart. Then you can refer to the video..if you forget what goes where.

Do it on a clean surface, so you don't lose/misplace parts

 

[Sander]

Re: FIRST Time on the lake! Few Hic-Ups!

Guys, I forgot to mention - there was a bit of hornet nest dust inside the engine bay, in theory, when I gave it a lot of throttle it could have possibly took in some of that dust in the carb - pointing to what you guys are saying on the blockage of the idle circuits! Sorry that I forgot to mention this, and now I feel like a bit of a fool for not completely cleaning the engine bay!

Been looking for carb kits, but no luck as I am uneducated on witch kit is for my motor! Any help in finding one for the 1971 Evinrude 100hp MODEL: 100193 would help me a lot! Thanks!


EDIT : Actually it turns out it is not a hornet nest, but infact the old foam on the motor case!

 

[Kaplooi]

Re: FIRST Time on the lake! Few Hic-Ups!

http://shop2.evinrude.com

Is the Mfg parts store. They list 383906 as the repair kit. Probably not the best prices but they have complete parts lists with exploded diagrams which is helpful if you don't have a service manual. It looks like on your carb you'll want to take out the needle valve and clean all the passages behind it as best you can. I believe they lead to some little holes behind the throttle plate which is where the gas comes out at idle but don't quote me on that.

As far as dust, it's dirty fuel that's more likely to cause carb problems than dirty air but that's not to say dusty air is good to suck into your crank case.

 

[Sander]

Re: FIRST Time on the lake! Few Hic-Ups!

So far, took the fuel pump off, and fuel filter. The filter screen looks pretty bad, and a lot of debris in front of it.

 

[Sander]

Re: FIRST Time on the lake! Few Hic-Ups!

I would check the needle adjustments on the low speed needle. They could be off a little. Fuel pump could possibly be getting week.

Did a bit of talking with my old man, he suggests the problem is indeed the Fuel pump. I hope that is the case, as I am really nervous about doing the carbs myself.

 

[Sander]

Re: FIRST Time on the lake! Few Hic-Ups!

Guys, I have discovered quite a few leaks, could this be causing the idle to bog down and die while everything is normal on high throttle? In any case I dont think its good. Here is the photo of the leaks, and the fuel filter screen. Any thoughts much appreciated!

 

[Daviet]

Re: FIRST Time on the lake! Few Hic-Ups!

It's always best to repair any fuel leaks when troubleshooting the fuel system. I bet you are still going to open the carb up and clean the low speed circuit.

 

[Sander]

Re: FIRST Time on the lake! Few Hic-Ups!

It's always best to repair any fuel leaks when troubleshooting the fuel system. I bet you are still going to open the carb up and clean the low speed circuit.

Thanks Daviet, for the support. I am really nervous and a little scared to take the carbs apart, have never done it before. I do have a service manual that goes over the steps, witch will help me a lot. Do you have any general tips or things to add before I start to dissemble? I will need a carb kit, two kits, yes?

 

[Daviet]

Re: FIRST Time on the lake! Few Hic-Ups!

You are going to need a kit for each carb. If you go to u-tube, I think there are some videos there by a guy called marine doc, he shows how to overhaul a carb simular to yours, I think.

 

[Sander]

Re: FIRST Time on the lake! Few Hic-Ups!

Daviet,

I did a test on my fuel pump. Took off the pump to carb line, got a temp line and cranked the motor. The fuel had strong spurts tapering off, not a constant flow, witch tells me the fuel pump is failing. I will get a new fuel pump tomorrow, and report back.