Difficult Cold Start

Tripp Halbert

Petty Officer 1st Class
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Jul 30, 2013
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1995 115hp. Motor is the 2+2 type. Runs pretty good and starts on the hose pretty easily after warm. but it is hard to start after it cools down or when in the water. Compression is 132 on all cylinders after warmed up. Spark is blue on all. Idle to wot is good. Oil injection currently in place. Just got motor and I wanted to make sure oil injection was working so I marked it to see if level dropped enough to show a functioning injection system. but during this i have ran 50 to 1 premix in the tank so im sure its running rich.

A couple of things that are bugging me:

-Engine pulses back & forth during different rpms near WOT by about 50 to 100 rpms?

-I heard the fuel line making a clicking noise and i grabbed it and it felt like a pulse?

-also, the primer ball will rev the engine when i squeeze it hard enough.

I thought i heard some knocking/ticking at mid wot but couldnt tell if it was in the midsection, the mounts, or power head. It didnt lose power or anything though. Also spotted water coming through the midsection gasket. Can there possibly be a bad cylinder or piston if it has perfect compression?
 

racerone

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Dec 28, 2013
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Post your starting procedure with ALL the details.---------Possibly you are missing some finer points on how to start an outboard motor.--------Too many folks are used to automotive starting where all you need to do is turn the key.
 

Tripp Halbert

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I've had a couple of boat motors so I'm familiar with how they should start. Here's my attempt procedure though.

Cold engine, on hose: crank it over no choke for a couple seconds. Stop. Choke and crank. Stop. Pump ball tight, crank. Engine starts. Warms up. Turn off and immediately back on, cranks. Repeat 4 or 5 times and it consistently cranks in less than a second of turning key.

Drop motor in river after warmed on hose. Same procedure and bit longer but it does well. Ran to an island. About 30 min drive. Let sit about 20 minutes. Went to crank and turned over but no fire. Choked. No crank. Primer ball squeezed. No crank. About 4 ttimes as long to get cranked and once cranked it seemed to want to shut off so I revved the warm up lever to 2k until warm. Then no problems. Got to boat ramp shut it off, cranked it immediately and it cranked no problem... weird right??
 

finish line 88

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Jun 25, 2008
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I can tell you what I found with my 2003 mercury 115 hp. It was hard to start when cold. I found where I had changed the inline filter I used zip ties on the fuel line. When I squeezed the ball I was getting a very small amount of fuel leaking at the connection. I also rebuilt the fuel pump and the same happened there. I removed the zip ties at got small stainless hose clamps to fit the fuel line. It made a world of difference . It must have been sucking air. To start pump ball till firm. Set throttle about half way. Turn key to on position. Push key in for 5 to 8 seconds. Turn key to start. Hope this helps. Good Luck
 

Tripp Halbert

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I did change the fuel filter but never tried Ss clamps. I will try that!
 

Bosunsmate

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I've had a couple of boat motors so I'm familiar with how they should start. Here's my attempt procedure though.

Cold engine, on hose: crank it over no choke for a couple seconds. Stop. Choke and crank. Stop. Pump ball tight, crank. Engine starts. Warms up. Turn off and immediately back on, cranks. Repeat 4 or 5 times and it consistently cranks in less than a second of turning key.

I wouldnt try starting until you have pumped ball tight otherwise itl be dry in there
 

Bosunsmate

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A couple of things that are bugging me:

-Engine pulses back & forth during different rpms near WOT by about 50 to 100 rpms?

-I heard the fuel line making a clicking noise and i grabbed it and it felt like a pulse?

-also, the primer ball will rev the engine when i squeeze it hard enough.

Does the primer bulb hold firm with engine off? it might have a leaking float valve or the pump might be going bad
 

Bosunsmate

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I thought i heard some knocking/ticking at mid wot but couldnt tell if it was in the midsection, the mounts, or power head. It didnt lose power or anything though. Also spotted water coming through the midsection gasket. Can there possibly be a bad cylinder or piston if it has perfect compression?

Which gasket is the midsection one?
Check the pistons bearings for play, move the pistons to TDC and with something that wont mark the piston head push on them and see what movement you get, it shouldnt be more than a hairs breath, feel between pistons and notice if theres any difference
 

racerone

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Dec 28, 2013
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Key is to be pushed in while cranking the motor over.---Have you checked operation of the enricher valve when key is pushed in ?
 

Tripp Halbert

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Which gasket is the midsection one?
Check the pistons bearings for play, move the pistons to TDC and with something that wont mark the piston head push on them and see what movement you get, it shouldnt be more than a hairs breath, feel between pistons and notice if theres any difference

Bosunsmate, I had the boat on plane and noticed water dribbling down the port side of the midsectin from i believe the gasket that joins the powerhead and midsection. the cowling was on so i didnt get a real good look inside to confirm the location. i will do better inspecting on all this saturday when theres some daylight to go for a test drive.

also, what is this TDC you mentioned? and do you mean for me to poke through the plug holes to see if the pistons have forward/backward play?
 

Tripp Halbert

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Key is to be pushed in while cranking the motor over.---Have you checked operation of the enricher valve when key is pushed in ?

Racerone,

yes i usually crank over first then push the key in and crank. i have confirmed enricher valve works but have not confirmed key is properly engaging it. do i just put the wife up front to push crank and listen for the enricher valve to operate?
 

Bosunsmate

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Bosunsmate, I had the boat on plane and noticed water dribbling down the port side of the midsectin from i believe the gasket that joins the powerhead and midsection. the cowling was on so i didnt get a real good look inside to confirm the location. i will do better inspecting on all this saturday when theres some daylight to go for a test drive.

also, what is this TDC you mentioned? and do you mean for me to poke through the plug holes to see if the pistons have forward/backward play?
Yes thats it, the way i check for that is at TDC, top dead centre- where the pistons at its most extended reach highest compression.
You dont have to get it to exact tdc just push on the piston when is there and notice what play it has then turn the flywheel back a bit to reset it then forward again to tdc and double check the play and then compare that to the other pistons.
If the bearings a shot you will notice quite a different amount of give when you push on it compared to the others
 

Tripp Halbert

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okay cool. personally ive never spun it before like that. Spinning the flywheel manually is okay clockwise and not counterclockwise, right?
 

Bosunsmate

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okay cool. personally ive never spun it before like that. Spinning the flywheel manually is okay clockwise and not counterclockwise, right?


Just take the plugs out and make sure the key is turned off. I spin it manually clockwise as i move each piston to TDC and back a little bit counterclockwise when i recheck each one before moving on to the next
 

Tripp Halbert

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It's still around 145. Degrees. Let it set 5 min. Have to crank a couple time to get it going.doesnt want to stay running so i Hold the warm up lever forward to hold it @ 1k rpms and then it slowly rises rpms over about a min and I'm now backing warm up lever down as it climbs rpms every 20 seconds or so irraticly. Now it idles at 900 to 1050, bounces up and down every now and then........??
 
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GA_Boater

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Tripp - Merged both of your threads so everything is in one place.
 

GA_Boater

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Okay thanks. Reason i did that was I have a merc but never get good feedback on that mercury forum.

No wonder. It's going back to the Merc forum. You have to allow time for members to see your thread because you are missing out on the advice from the Merc guys. This is the time first in this thread you mentioned you are working on a Mercury. I don't know if much of what you got here will apply to a Mercury outboard except the generic responses.

Please post Mercury questions in the Mercury section, not in the Johnson-Evinrude section. Thanks.
 
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