Anyone experienced with Merc 3.0?

[ME_man]

I’m having a poor starting/running/no power issue which I believe I may have narrowed to valves and/or adjustment.. my question is this: I’m cranking the engine with a starter switch.. plugs out/Ign off.. I have fuel blowing out the #3 plug hole only. Is this normal? I would think it should be coming from all of them(or none?). I just replaced the pushrods/lifters/rockers because the pushrod to #3 intake valve was bent..
Any help would be appreciated.

 

[alldodge]

I have fuel blowing out the #3 plug hole only. Is this normal? I would think it should be coming from all of them(or none?)

No not normal and also should not be happening with any of the cylinders. With plugs removed there would be very little vacuum pulling air thru the carb, so very little fuel would make it. Probably need to pull your carb apart and find out why its flooding the motor.

I just replaced the pushrods/lifters/rockers because the pushrod to #3 intake valve was bent..

What caused the push rod to get bent?

 

[ME_man]

I’m not sure what caused the pushrod to bend.. all the valves moved freely.. I replaced it because it was noisy.
Ive had this boat a couple of years. Bought it not running and know nothing of its history. A new distributor got it running. Now I’m trying to get it running”right”.
What might I look at in the carb that would cause this problem? I’ve checked and reset the float level and drop twice. Replaced the needle and seat. Replaced the float. I set everything per the workshop manual.
Could the flooding also cause it have no power? It seems to go ok up until about 20mph where it bogs out.

 

[ME_man]

Also there was no indication of piston to valve contact when I had the head off...

 

[ME_man]

If the carb is flooding the engine.. I guess I’ll try moving the float level down a bit...?

 

[Bt Doctur]

pushrods bend in a few ways.
Valve stuck in head from moisture
piston hits valve

 

[alldodge]

Crank the motor and see if there is more then just a slight mist being sucked in. If its flooding, then need to get back into the carb

If it runs good up to 30 and not after, then could be timing, compression, carb

Do a compression test

 

[Scott Danforth]

most probable cause of bend push rod is water in the cylinder, causing valve to rust to head - coming from a cracked or rusted exhaust manifold.

 

[ME_man]

No way it goes 30.. 15-20mph.
I will do another compression test.. it was good before I pulled the head off and I was having this power/starting problem then.. I thought maybe water was getting in the engine. All were at 140 psi except cyl 4 which was @136. I’ll recheck compression. I just readjusted the valves. I’ve also changed out the ignition coil and module with used parts to see if there is any change.
One thing I did notice after I set the timing-yes I know the special process for EST- At idle the timing jumped around a lot... did not seem to advance to 12*

 

[Bt Doctur]

with the plugs out there should be no vac to pull fuel into a motor, could the mist be water?

 

[ME_man]

“with the plugs out there should be no vac to pull fuel into a motor, could the mist be water?”

I suppose.. although it smelled like fuel.. also the boat was out of the water for 24hrs and did not have a hose connected.. I’m sure water was still in the exhaust manifold..
I had fired up the boat briefly twice early to test the used ignition parts.. fired right up without a prime.. then was working on the tach which the privious owner had replaced and set the pulse wrong.. went to start 3rd time to check the tach and it was acting flooded. So I opened the throttle all the way and cranked it until it fired up.. ran like hell for a couple secs.. I backed off the throttle and it started to clear itself and died. I pulled out the plugs.. what looks like exhaust comes out #3 plug hole. Once the smoke cleared I cranked the engine with the starter switch to see what would happen and what I believe was fuel comes blowing out of # 3 in time with the engine.
I should also note cyl 3 spark plug was the only one visibly wet of the 4.

 

[ME_man]

The boat had been sitting prior to me purchasing it.. the previous owner said it died on the water. He couldn’t figure out what was wrong and was not much of a mechanic. I found that someone had disconnected the lanyard switch which wouldn’t allow power to the coil.. it still wouldn’t start. I found the distributor was bad(prob why it died on the water).. with new distributor it started but has always had this no power issue. I’ve rebuilt the carb. Checked the float level and drop twice. Would anything other than carb flooding cause this? If not I’m tempted to buy/try another one. I’d like to have this thing operational for next weekend.

 

[ME_man]

The boat had been sitting prior to me purchasing it.. the previous owner said it died on the water. He couldn’t figure out what was wrong and was not much of a mechanic. I found that someone had disconnected the lanyard switch which wouldn’t allow power to the coil.. it still wouldn’t start. I found the distributor was bad(prob why it died on the water).. with new distributor it started but has always had this no power issue. I’ve rebuilt the carb. Checked the float level and drop twice. Would anything other than carb flooding cause this? If not I’m tempted to buy/try another one. I’d like to have this thing operational for next weekend.

Sorry.. this is kind of the back history..the timing of these posts and timeline aren’t as they happened.
I have had this power issue ever since I got the engine running.. have been doing this and that to try to figure it out.

 

[ME_man]

I have also replaced the fuel filter and pump.. fuel seems to be flowing freely to carb.

 

[ME_man]

Just tested compression. 145 on #1.. 150 on the other 3

 

[ME_man]

I’ve readjusted the float level and drop.. seems to run a bit better.. I’ll know once I put it in the water..
thanks for the help/advice

 

[alldodge]

Good to hear, look forward to updates

 

[ME_man]

Just got back from a test run.. boat went MUCH better. I was able to get on up to a little over 35mph.. 4000 rpm trimmed up a bit.
It still doesn’t really jump like I’d like to get a skier out of the water. Also it will only go to about 3/4 throttle before it bogs. I’m thinking maybe a slight adjustment to the float.. but to the level or drop? Any thoughts?

 

[alldodge]

Bogging is mostly caused by the motor getting to much or to little fuel. The issue is in the carb, float level, (assuming Merc carb) main jet circuits (need to be clean). Could also have a fuel pressure issue, should be 3-7 psi