Hard starting 140 V4 OMC

" Thanks in advance for any he

" Thanks in advance for any help given!
Let me try to give a little info first to help in the diagnosis.
The motors are 1989 140HP V4 OMCs. Engines run off of common fuel supply, seperate fiters and primer bulbs. One starts and runs fine, other is hard to start, stalls sometimes both in gear and in warm up @ lower rpms (>1500) occasionally will stall at cruise, not very often. Motor will not take throttle until it runs for a while (5-10 mins) whether warm or not. Motor will not start well warm or cold. I have not done any checks at all. the only thing I did was replace the plugs. Didn't make difference but I looked at them and they seemed to a alot of wet carbon on the port plugs. Sounds like fuel to me. VRO? Carbs? Compression reads aprox 92 Psi, which I understand is ok on this motor. Once motor is up and running it seems ok until you back down the throttle.

Thanks
Scott "

Any ideas Joe? I was told if

Any ideas Joe? I was told if anybody would know it would be you! Thanks
Scott

"Scott... I was waiting to see

"Scott... I was waiting to see if you were going to do any checks. Compression should be in the range of 100 psi and "EVEN" on all cylinders. With the s/plugs removed, do a spark check.

The spark should jump a 7/16" gap with a strong blue flame on all cylinders. Weak ignition through out (spark) usually indicates that the stator (under the flywheel) is cracked and failing (usually shows signs of melting down). Also weak ignition could be contributed to a ignition switch that is failing. The switch can be checked by simply removing the black/yellow wire from the back of the ignition switch and re-test the spark.

Your description of the spark plugs could indicate weak ignition (stator). To really check that stator, it's best to remove the flywheel to inspect it visually. NOTE... be sure to torque that flywheel nut to 145 foot pounds!

If the above is okay, (still with the s/plugs removed) remove the carburetor face plate and disconnect one of the primer hoses that leads from the fuel primer solenoid to the intake manifold. Pump the fuel primer bulb until it's hard. Now, while you're holding that disconnected primer hose, have someone hold the ignition key in (fuel prime/choke position) and crank the engine. Fuel should shoot out of that primer hose. If it doesn't, find out why.

The s/plugs should be Champion QL77JC4 plugs, with their gap set at .040 .

With the carb face plate off, run the engine and (one carb at a time) stick two fingers into the carb throat to richen the mixture. If the rpms pick up and the problem ceases at any carb, that carb is fouled. Let us know what you find.

Joe "

" Here is what I found Joe. Sp

" Here is what I found Joe. Spark looked good strong blue flame across 7/16" gap. After seein this I skipped to fuel.(I didn't check the stator since spark looked good.) Removed primer hose, pressed key in, shot out alot of oil, maybe a 50/50 mix, at best. couldn't really get it started to check carb mixture with the method you described. I will continue to try to start the motor to try the carb check.

Thanks
Scott

BTW: Where are you at Joe? Sounds like I may owe you a few beers very soon! "

" Joe,

Here is the latest.

" Joe,

Here is the latest. Got engine running. Fixed Tach (a wire was loose, unrelated) Carb trick really didn't have much of an effect. What I did notice was alot of oil around the carbs (clean two stroke) and lots of black oil coming from the exhaust. It seems everything that you suggested to check seems ok, except the carbs running too lean, the engine ran a little rough and didn't seem to get better by putting my fingers in them. The plugs are still wet, does this seem to indicate a rich oil condition caused by a faulty VRO pump?

Scott "

"Scott.... Since you are runni

"Scott.... Since you are running both engines off a common fuel tank, and the latest info you've forwarded about the extremely high oil rich mixture shooting out the line, I would be leaning in the direction of a failing VRO pump. A 50/50 mixture, if the engine ran on that, must have killed every mosquito in your county.

The only other thing I can think of would be a fuel restriction in that one engine, and that would have to be between the inlet side of the VRO and the fuel supply pickup. If there are two seperate fuel pickups in that tank, you may have a sticking "Anti Siphon" valve where the rubber fuel hose attaches to the pickup. The valve would be aluminum, about 2" long, and the insides would consist of a "ball, ball seat, and a spring". If that valve exists, knock out the insides and re-install it as a straight through fitting. (A fuel restriction causes the VRO to pump less fuel, and excess oil).

Joe"

" Thanks Joe, I also have duel

" Thanks Joe, I also have duel tanks and the problem occurs with either tank on the one engine, sounds like failing VRO I guess. It does smoke quite heavily when started, especially after cranking for a bit. Any good sources online for parts? Is there a way to test the VRO?

Thanks
Scott "

"Scott... You asked where I wa

"Scott... You asked where I was, sorry, didn't answer... Central West Flordia, just east of Tampa. The easiest and fastest way to check a VRO would be to clamp off the oil line close to the engine so that it couldn't draw any air or oil, and connect a portable tank that has a 50/1 fuel/oil mixture to the engine in place of the regular fuel line. This will force the VRO to act as a normal fuel pump. For this test, also disconnect the VRO warning system at the rubber electrical connector (follow the wires from the back of the VRO to the connector), otherwise the "No Oil" warning will drive you nuts.

Note... Can't buy me any beer, had to quit that stuff years ago (not my choice). However, Ham & Eggs & Home Fries sounds good!<grin>

Joe"

" Joe,
You are a good w

" Joe,
You are a good ways off, I am in Delaware. Wish I could meet ya and buy you breakfast! Well I am hoping to get down that way someday.

What should I look for (I am assuming a clean running engine that doesn't load up with oil) I am guessing a VRO could go bad in two ways, the oil(too much or little) or the fuel. Wouldn't the fuel side pumping too little fuel richen the oil mixture too? I think its probably pumping enough fuel just too much oil and it is fouling things up.

Thanks for my education!
Scott "

"Scott... You asked "What

"Scott... You asked "What should I look for? I am assuming a clean running engine that doesn't load up with oil?"

Yep... that's it, and your other assumptions are correct.. Cross your fingers.

Joe"

" Hey Joe! I posted a message

" Hey Joe! I posted a message but I guess it didn't take.

Well the motor runs alot better with hooked up to premix. There is still a misfire, but I'm sure that the plugs are fouled from running so oil rich. Gonna change them out and it should make a difference. What are my options for the VRO. I know I can run premix or replace the pump. Is there a rebuild kit for the pump? Took the pump apart today and I think the check valve is leaking. It doesn't appear to be seating correctly. Also there is a small tear in the diaphram that separates the "mixing chamber" and the fuel intake resevoir.

One other question:
These motors are on a Seadrive bracket. What are my repower options. I would like to go with EFI or 4 stroke in the future. Thanks again Joe, you are a lifesaver!

Scott "