1989 Merc 30l

"Hi,
New to the forum and

"Hi,
New to the forum and need a few ideas on my 3.0l merc. It fouls the plugs but only when trying to go under power. Had a problem with the choke and it is wired open right now so it can't close. Then we took the boat back out and hit the throttle and the boat started to go and then died down. Started back up and same thing so turned around and went back in motor was running rough and barley made it back before it quite. Compression is good, new plugs, points, rotor, and cap. Timing is right on and steady. Idles good now choke is fixed and revs good. Just found a bad connection on the coil. Think that could do it? Usually I have no problem fixing a motor but this boat has been a nightmare since I bought it. It's a 17" Winner (Yea right a real winner). But the boats rides nice when it runs. Thanks for any input."

"Use a dwell meter on the poin

"Use a dwell meter on the points. It should stay at the spec, if you rev the engine and the dwell changes the distributor has a problem holding the points. Maybe the top bushing in the distributor is bad. This occurs alot in boats that were trolled alot."

Sounds like you carb needs a r

Sounds like you carb needs a rebuild. Either that or you have water in the fuel (common boating problem--you don't think the marinas are only selling you gas for your 4 bucks a gallon!)

Jeff

"Ok,
I have checked the dwe

"Ok,
I have checked the dwell and it stays the same. It is set at 32 deg (28-34 says book). Engine runs great just rechecked compression and #1-155, #2-160, #3-160, #4-152. Timing is at 6deg BTDC and is steady. Engine does not foul plugs while running in driveway since choke was fixed. The wire on the coil was the starting wire and would explain why it would only start when the key was released once in a while. So that was no the problem. Mainly the problem now is when it is out on the lake and you open up the throttle it dies down and fouls the plugs. Then the plugs need to be taken out and cleaned before it will run good again. One question I have is while checking spark with the new plugs, they have been fouled 5-6 times real bad, is the plug sparks from the center elctrode to the side and not to both electrodes. Anyone now why, is it because they were fouled so many times? Just curious about that. Will get a new set of plugs Monday. Hate to just take the boat back out without finding anything else. But I do think that if the plugs were not firing between the elctrodes when alot of fuel gets dumped in by opening the throttle that the plug would not be able to fire and the plug would foul. Just a thought. But this problem seemed to come up last year when I went to take it out it would only run at 2000rpm and below like now. But after putting in dry gas and new plugs, rotor, cap, points, and cond (new plug wires last year) that it would run good. Rebuilt the carb last year. Just about to take that back off and go thru it to make sure nothing lossened up in it. (I have rebuilt many carbs so really not thinking I'm going to find much) but worth a shot. Anyone else have any ideas?? Not sure where to go from here. It is driving me crazy running so good in the driveway but so bad out on the water??"

"Just found gas in my oil, fro

"Just found gas in my oil, from reading another post. Quite a bit of gas in the oil so I'm thinking that the engine is not getting lubed enough under power. Not what one wants to find as the problem. Will be changing oil and trying it out Monday. Will post results. Anyone know why ghas gets in the oil? Thanks"

That carb is dripping fuel int

That carb is dripping fuel into the intake while its running and after its running. Either the needle and seat are bad or there is a welch plug in the bottom of the carb that is leaking all the fuel out. Look that carb over good. You can bench test the fuel bowl leak.

"Thanks Harves, I will take th

"Thanks Harves, I will take the carb out and tear it down. I will post results when done. Thanks everyone for the help so far!!"

All that gas in the oil is ano

All that gas in the oil is another indicaton that the carb is flooding.

Jeff

"Well took the carb apart and

"Well took the carb apart and everything looked good. put in new needle and seat (old one looked good but decided for $17 change it). Guy at boat store said gas in oil could just be from trying to start it in the spring since I didn't really look at the oil since I had a hard time starting. I am very curious why some of the old plugs fire from the electrode to the side and not to the top electrode (most of the time not all), this is bothering me because it would seem the engine would not want to run at high speed under load. Will launch it tomorrow and see how it runs in the lake. (crossing all fingers)"

"Well just got back and no go.

"Well just got back and no go. Motor runs perfect but hit the throttle and it will go to 3000 rpm but no more. Boat is standing on end but will not get on plane. Fouls the plugs while throttling but then runs good in a couple seconds. Pulled the plugs and they are heavy soot on the sides and the top elctrode is burned back and the center cermaic is white and the center electrode is clean. Looks like it fouls then burns the soot off while going back to the dock. It runs great at 2000rpm but keep going up and starts to bog. I can't figure this out. What about a partial exhaust blockage? But revs great in drive from a idle. The motor runs so good in the drive you can't hit the key fast enough so the engine doe not start. It starts and runs perfect. Go out in the am in the cold and hit the key no choke, no gas 2-3 turns and starts.But no power. Watched the timing advance and it goes out of sight due to my motor mount. Any ideas anyone? Thanks"

"Look at spark plug gap, remov

"Look at spark plug gap, remove a plug and install into plug wire, ground it and have assistant crank it over, check spark across plug, should be nice and blue, not white or green. I didn't see in your post that you replaced the wires. Wires are junk. How about the coil, get it tested free at your local parts store or NAPA. Last test, remove the wire to the coil that has the shift interupter, do it out on the water. You won't be able to get it out of gear with the wire off. Hit the key, engine off to get back to neutral. Good Luck"

"harves marine, do the shift i

"harves marine, do the shift interupter switches go bad very often? i've been working on 140 mercruser and cannot get any spark out of coil wire. i got voltage to both sides of coil and to points. it's got new plugs,points condenser,cap rotor,coil and plug wires."

"The spark is nice and fat and

"The spark is nice and fat and blue. Before the wire to the coil from the starter circuit was corroded and I did not have a good spark while cranking, sometimes the motor would only start when I let off the key. Last time out the coil was one I had on the shelf from my other boat. Wires I bought last year and have changed 2 wires with the old ones that ran fine when I took them off. The shift interupter test wouldn't show me much since when on land the boat even in gear revs to max rpm with now hesitation at all. The motor runs at 2000-2200 rpm strong and pushes the boat around with the correct amount of power. With the spark plugs carboning up so bad, and I mean from clean to thick soot in under 2 minutes running the motor at full throttle in 15-30 second bursts. Seems like it wouldn't be a gas problem due to the sooting. I am thinking there may be a problem in the outdrive. Has anyone ever had a outdrive hold the motor back? That is almost what I feel running the boat. The previous owner hit something in the water and never told me but the lower outdrive is a different shade than the rest and the engine coupler was broke when I got the boat. When I replaced the coupler the outdrive seemed fine but did not pull it apart.Any Ideas anyone?"

"tom f
the shift interupter

"tom f
the shift interupter grounds the coil wire on the points side of the coil, so you would not have any voltage on the coil on the minus side. Coil is probally shot."

You could have an outdrive tha

You could have an outdrive that was replaced with the wrong ratio in the upper housing. Even a V6 outdrive would not be happy on the 4 cyl.

"Well just got the upper gear

"Well just got the upper gear housing off and the ratio is 1.32:1 I believe,(the engine shaft turns about 1 1/3 times and the output shaft turns 1 time), far cry from the 1.98:1 ratio it should be. I always wondered because the boat should do 45-47mph and will only do 31-33mph once in awhile it would go upto 38mph. And it always had a hard time planning. I put a different prop on to get the rpm's where they should be.
So I'm thinking it could be a smaller problem that reduces performance in motor or outdrive and the ratio is keeping it from getting on plane, atleast that is one idea in my head right now. Also i have a question for the lower unit. The vertical input shaft moves up and down just over 1/16" and side play is a little less than a 1/16". Is this normal? Seems like alot to me but never really paid attention to that before. Also the bellows for the u-joints is leaking water and there is a small amount of water in the bottom of the bellows. The u-joints are smooth but a little rusty on the surface. So not really sure where to go now. Really need a place to dyno the motor but funds are limited right now. Can the gears in the upper gear housing be changed to a different ratio or does the housing limit that? And Harves your right about a v6 not liking it just think how this 454 housing feels."

"Larry, well you found it. All

"Larry, well you found it. All that load on the engine. It could not handle it. All your observations relative to the vertical shaft are normal as long as you are talking Alpha. The water in bellows problem may be the large rubber ring was displaced by the last person mounting the drive. This fact keeps me very busy. Folks mounting their own drives should be gluing in the ring. Lube the ujoints and grease the outside of the yoke and ujoints. You can have the upper gears changed to the right ratio. They just need to be shimmed by someone that knows how and has the tools. Good luck, No dyno required. Harve"

"Thanks Harve, I rebuilt my vo

"Thanks Harve, I rebuilt my volvos and they ran great. I have experience with rear ends in trucks and applied it to the outdrive and bought all the tools last time instead of paying for it to be done. I know you guys sometimes don't like to hear that but only a few of us get it back together and running the rest bring it in to you to finish (which possibly could be me but not usually) LOL. Yes it is a Alpha one gen 1. If there is anything you want to pass on to me a few tricks when doing the outdrive I'd be happy to hear from you. I have an email at lpm1atexcite.com (replace the at with @, not sure about this sites rules on posting email addresses). Still not sure why it would get up and go last year and not this year. Seems like the engine is running just as good as last spring or a little better. And used it all summer, it would take a little bit to get on plane but it would without loading up the plugs? The big ring was in place and seated. Not sure but the shifter shaft seal might be worn. What kind of glue are you using to glue in the ring? And another thank you very much for all your help. Its awsome to have someone be able to answer all the questions that and can only be answered by someone with the experience (nothing can replace experience). Thanks again and have a good one."

"That poor mill is loading up

"That poor mill is loading up 'cause it can't plane off with those high gears. Blast, 'cause that's the toughest (read: $$) thing to correct.

Good luck,

Jeff

PS: My old 19 ' Bayliner with that engine also ran 45 mph."

"Use bellows adheasive on the

"Use bellows adheasive on the OD and one face of the ring. When the adheasive does not transfer to your finger, install it. After the ring is in put a little grease on the ID and sealing face. Thanks for the kind words"

"Thanks for the advice on the

"Thanks for the advice on the bellows and ring I will follow for sure! and after looking in the book I see there are 2 tools to do the head that are essential. Whish they gave specs to do a backlash adjustment instead of the face to face tools, but oh well. Thanks again"