noisy idle with a 1972 Evinrude

[RJ2986]

Hey guys I am new to the forum and in need of some help. I just picked up a 1972 Glastron V163 with a Evinrude 100hp (100293R) and it's in great shape for it's age due to the fact it has hardly been used. But due to the fact it sat in a boat house most of its life probably wasn't that great for it ether. Last time it was run was 2004.

With that being said the problem I am having is the motor seems to have a rough idle. Not the normal about to stall idle but more of compression problem perhaps? I know car engines inside and out but this is my first 2 stroke engine and from what I hear this engine is a tricky one but the good news is is the electric shift works like a champ. I posted a link for the video i uploaded on youtube. Any help or advice would be greatly appreciated.

Link to the video:
Not sure if this sounds good or not... - YouTube

 

[Bosunsmate]

Re: noisy idle with a 1972 Evinrude

Hi
Nice retro controls.
Hard to tell if its a knock in there from the video.
do you have a compression gauge from your car work? Check the compression numbers and also consider changing the fuel lines and cleaning the carbs as that will set you up a good base.
Bits of old hoses breaking off and falling into the carbs can cause bad problems such as running lean which really stuffs a two stroke.
The little passages and jets need a thorough clean to be sure that there is no lean idle condition. you shpuld also change the fuel filter and pump diaphram and impeller and gear oil since its being sitting on its backside for near on a decade.

 

[RJ2986]

Re: noisy idle with a 1972 Evinrude

Completed a compression test and got the following numbers. Not sure what the normal compression is in these engines but I heard its around 130psi? correct me if I am wrong...

Cyl 2- 135 psi
Cyl 4- 130 psi
Cyl 1- 130 psi
Cyl 3- 125 psi

I believe the stranded tolerance for compression is to be within 10% of the original specs... so this may be a fuel/carb problem at this point... not a big fan of working on carbs but at least it looks like I narrowed it down a little bit.

 

[emdsapmgr]

Re: noisy idle with a 1972 Evinrude

Your compression should be 125 plus, so from the compression standpoint, your engine is in good shape. It really sounds good, even if it has not been run lately. Hard to tell just what the idle situation is, running on the hose. It probably is idling about 1200 or so on the hose. You really need to get the boat floating normally, where the prop/exhaust outlet is 20" underwater. That backpressure will really tell just what is going on at idle. Once it's floating, you should set the idle. (can't do it on the trailer.) Set the idle to 650-700 rpm's when shifted into forward gear. Once you get it set correctly-then you can evaluate how it idles.

 

[kenmyfam]

Re: noisy idle with a 1972 Evinrude

Have to agree. Put it in the water to properly evaluate.

 

[RJ2986]

Re: noisy idle with a 1972 Evinrude

Thanks for the help everyone, I will have to give it a shot in spring... Just had our first frost today and 40 degree temps the rest of the week so it will have to wait unfourtaually. Gotta get the boat winterized before it gets much colder.

Also one more thing do you know the sure fire way of telling if the water pump is working on this motor? I didnt see a bypass on the lower shroud.... Ether way im going to rebuild the pump and replace the t-stat.

 

[emdsapmgr]

Re: noisy idle with a 1972 Evinrude

That engine does not have a telltale-came out on the 78 year models. Here's your test. Start the engine cold. Stand back by the rear of the engine and hold your palm by the two exhaust relief ports at the top of the midsection. After a minute of running (or so) the thermostat will open. When this happens, water droplets will start to form on your hand. That's normal operation. If the pump's a problem you won't get the mist out of the relief holes.