OMC Guru's---Dhadley, Walleyehead, anyone....

[tysidor]

Re: OMC Guru's---Dhadley, Walleyehead, anyone....

Walleyehed-- Let me get this straight. My timing advance screw has two slots for a screw driver. There is one under the rubber stopper and the deeper slot on the opposite side where I am making my measurements. I am assuming the side that you should turn as far as the Clockwise/CounterClockwise is concerned is the side opposite the rubber stopper where you measure? Is this correct?<br /><br />I was trying to verify timing tonight, but I had two problems. First off my eyes got dialated today at a doctor appointment so I wasn't seeing very well. I couldn't get an exact reading, but it looked like my timing was reading 20-22. The timing gun I had has a setting where I can put in a timing # and it should read at 0. So I put 28 into it and it was reading 8. Does anyone know if this means it is to advanced or to retarded? I am assuming if I was reading my 20-22 that the 8 reading means I am 8 degrees retarded. Heck who knows I guess I will try tomorrow when I can actually see. <br /><br />Is it safe to set timing on muffs as long as you are in gear and have a lot of water going through the engine? This would sure be a lot easier.<br /><br />Thanks everyone!!

 

[OBJ]

Re: OMC Guru's---Dhadley, Walleyehead, anyone....

DO NOT try and set the timing on muffs. You could blow the engine. Go back and read my post on setting the timing with out the engine running. It works. Then if you want, verify the timing with the engine in the water and running at WOT.

 

[tysidor]

Re: OMC Guru's---Dhadley, Walleyehead, anyone....

OBJ---I am confused about one part of your method. Do I just need the spark tester in the #1 cylinder? What is the purpose of the spark tester? Sorry, for the dumb question but I am a little unclear as to what needs to be done.<br /><br />Thanks.

 

[OBJ]

Re: OMC Guru's---Dhadley, Walleyehead, anyone....

You'll need the spark tester on all cylinders ty...to get the timing light to work, you need to get the pulse through the spark plug wire...that means it's got to be going to ground. You'll need the other cylinders to do the same thing just to protect the electronics of the ignition system. Simply put, without the spark plugs in, you need a place for the spark to go. There was a good picture in one of the threads of a home made spark tester....wish I could find it.....:-(. I'll keep looking.

 

[tysidor]

Re: OMC Guru's---Dhadley, Walleyehead, anyone....

Well I finally had time to check the timing. I tested it at WOT in the water. It looks to be very close to 28. Sometimes the light would blink slightly lower and sometimes slightly higher. I didn't change it at all. While I was out there I double checked for spark at WOT on all cylinders. All cylinders were firing at WOT. <br /><br />I did find that at WOT if I started pumping the primer bulb my rpm's would jump up 200-400 rpms. What does this mean? Are my fuel pumps not supplying enough fuel? Do I need to completely rebuild my carbs? Maybe my problem is directly related to this. Any idea's? <br /><br />Thanks guys.

 

[Basscat 1]

Re: OMC Guru's---Dhadley, Walleyehead, anyone....

If you gained 200-400 rpms by pumping the primer bulb, you have found a problem.<br />By chance, did you check your fuel tank vent? The tank needs to be vented. Also look for any restrictions in your fuel lines, or loose clamps.

 

[tysidor]

Re: OMC Guru's---Dhadley, Walleyehead, anyone....

Fuel system is just fine all of the following has been replaced. Tank, line, bulb, fill hose, vent hose,connectors, and fuel filter (water filter). No restrictions can be found. Tank is venting properly.<br /><br />Maybe the fuel filter/water separater is the problem? I didn't have one of these until I put a whole new fuel system in.

 

[walleyehed]

Re: OMC Guru's---Dhadley, Walleyehead, anyone....

3/8" fuel line all the way????

 

[tysidor]

Re: OMC Guru's---Dhadley, Walleyehead, anyone....

Here is an exact layout of fuel system.<br /><br />27 Gallon tank in bow of boat. I don't remember the brand. Got it from Overton's---had some credit.<br /><br />New Bombardier Fill hose 1 1/2"<br />New Bombardier Vent hose<br />3/8" Bombardier fuel line from tank to fuel filter and from fuel filter to primer bulb then from primer bulb(OMC)to engine.<br /><br />All misc parts are OMC (quick connect, barbs).

 

[Basscat 1]

Re: OMC Guru's---Dhadley, Walleyehead, anyone....

27 Gallon tank in bow of boat. 3/8" Bombardier fuel line from tank to fuel filter and from fuel filter to primer bulb then from primer bulb(OMC)to engine.<br />

How is the fuel transfered from the bow of the boat to the motor? That seems like a lot of "stuff" for the fuel to have to go through just to make it to the engine? Just a suggestion. You may need an electric fuel pump coming out of tank.

 

[tysidor]

Re: OMC Guru's---Dhadley, Walleyehead, anyone....

It is a long way for the fuel to travel, but it has always been setup this way minus the water filter. <br /><br />I don't think this is the problem though because I tried hooking it directly to a 6 gallon tank with a 5 foot long fuel line 3/8" and still had the same problem.

 

[Basscat 1]

Re: OMC Guru's---Dhadley, Walleyehead, anyone....

What kind of fuel filter are you using? I have been told not to use an in-line fuel filter because of the risk that the filter may actually restrict the oil from the gas if you pre-mix your gas and oil. If you dont pre-mix, disregard.<br />Did the fuel tank come setup in the bow of the boat, or did you move it there? 27 gallons full, means a lot of weight in the front.<br /><br />Switching gears. What hole is your tilt pin in? You said the AV plate is even with the bottom of the transom, but have you tried moving it up one hole just to see if you gain any rpms?

 

[tysidor]

Re: OMC Guru's---Dhadley, Walleyehead, anyone....

I am using a Mercury Fuel Separator. It is the same one that the local marina's are both using. It says right on the box that it is designed for 2 cycle engines with premixed oil. It says it does not serarate the oil. Should I change to a different type?<br /><br />As far as the fuel tank. All factory CVX-20's came with 27 gallon fuel tanks in the bow of the boat. I just replaced the one that was in there because there was some rust. <br /><br />My tilt pin is in second lowest hole. If I move it up a hole I will start to ventilate in turns. My engine is currently as high as it can go. If I did go higher I think I would be ventilating pretty bad. As far as gaining rpms---If I trim up while running WOT I will gain about 100rpms. Nothing significant.

 

[farginicehole]

Re: OMC Guru's---Dhadley, Walleyehead, anyone....

At the risk of asking a very stupid question, what exactly does that tilt pin do, anyways? Doesn't it just limit how much the motor will trim down?

 

[tysidor]

Re: OMC Guru's---Dhadley, Walleyehead, anyone....

Yes, the tilt pin just limits how far the motor can trim. If you have it too far up then the motor cannot trim low enough. It is like running with the motor trimmed up all of the time if you have it to far out.

 

[farginicehole]

Re: OMC Guru's---Dhadley, Walleyehead, anyone....

Thanks - that's what I thought. And if you're not reaching high enough rpm, you'd be more concerned with the motor not trimming high enough or being mounted high enough on the transom. Guess that's why I was a little confused as to why the tilt pin came into the discussion, that's all. I'm closely watching your thread because of low rpm issues with my '89 150XP. I raised my motor way up this weekend, but my tach was giving problems so I don't have a reliable new rpm to report. I did, however LOSE 1-2 mph according to the speedometer. Think I was cavitating a little if I trimmed it all the way up, so I dropped the motor back down one hole. It was as low as it would go, then I went to straight to the highest just to see what it would do. Haven't had a chance to check my timing yet, so I'm not as far along as you.

 

[Basscat 1]

Re: OMC Guru's---Dhadley, Walleyehead, anyone....

The fuel filter is the right type, however it may be restricting your fuel flow (meaning the amount of fuel traveling to the engine) thus causing a problem. If it didnt come with it, I would try by passing it and see what that does.<br />You said at WOT you get 5000 rpms, and when you squeeze the primer bulb you gained 400, plus when you trim the engine up you get another 100 which should equal 5500. Correct?<br /><br />The further the tilt pin is in (closest to the transom) the quicker the hole shot, but the top end will suffer. Moving the tilt pin out usually helps the top end, but the hole shot may be a little slower.

 

[tysidor]

Re: OMC Guru's---Dhadley, Walleyehead, anyone....

I can try bypassing it, but I don't think it will help considering that when I tried a 6 gallon tank it didn't make any difference. But who knows, right now I am willing to try anything.<br /><br />As far as WOT when pumping the bulb it would jump from anywhere to 200-400 rpms more. So yes, if pumping and trimmed as high as I can go I would guess I could hit 5500. <br /><br />I have not tried trimming and pumping at the same time. I just know that without pumping the bulb and trimming up I would hit about 5100. <br /><br />When pumping the bulb and not trimming it would jump to 5200-5400.

 

[Basscat 1]

Re: OMC Guru's---Dhadley, Walleyehead, anyone....

Remember, when trying to reach 5800 trimming up the engine is usually normal.<br /><br />Back the to pumping the bulb and gaining rpms. Right now this would be my biggest concern. Try by passing the filter first.<br />How does the engine fuel pump look? Have you tried rebuilding it or replacing it? <br />I think your not getting enough fuel to obtain higher rpms.

 

[farginicehole]

Re: OMC Guru's---Dhadley, Walleyehead, anyone....

Hey Basscat, I'm kind of confused about the tilt pin. Does moving it to the holes further from the transom actually give you "more" tilt when you trim your motor up as far as it will go? I just had the impression that the tilt pin only limits how far you can trim it down, and that it had no effect on how far you can trim the motor up.