Fine in idle, terrible when in gearSN2001

eyedsn2001,

Don't take this the wrong way but if you're not sure what you're doing at this point I think it's time to take to a pro and get the thing sorted out. You've already spent a bunch of money and it's no closer to running right. The marine dealer is backed up and that will only get worse so get it on his schedule now and then you can enjoy the summer without worrying whether the boats gonna run everytime you take it out.

I'll get on the schedule today. Problem is, speding more money to find out motor needs rebuilt/replaced, when I should be able to figure that out for myself.

Where's a good place to order a rebuilt/new 351 marine? That way I can see what I'm in for.

Agree, a good automotive shop that can simply fill a bucket of water for the raw water pick up would work, or fake a lake. I would find an automotive place that might be able to set you up with a re-build if necessary. The compression test is your best option right now. I'd stop spending money or replacing more parts. Keep us posted.

Ken

Compression test are simple to perform and cheap. Go buy a compression gauge at your nearby autoparts store. Remove the spark plug and screw in the gauge. Crank the engine over until you get the highest reading. Write it down and go to the next cylinder. Remember, the reading is not really the important thing. The important thing is that all the readings are within 10% of each other. If one or more are way down, you then know you have a problem.

I suppose you could have stuck rings that occurred during the storage period. If you get a couple of low readings, pour about 1cc of Marvel Mystery oil in the cylinder and let it sit over night. Long shot here, but it could happen, I suppose.

Are you saying that when you tighten the distributor hold down clamp (bolt) the engine starts to bog? If so, check your timing after you tighten the clamp to see if it changes. It's normal for it to change some and you may have to compensate for this before you tighten the bolt. If this is all that you're talking about it's simple to fix. However, the way you are discribing this makes me think that something is binding when you tighten the bolt down. Could this be your problem?

I think you are starting to pinpoint the cause of your issues. Let me say that just before I sold my '77 Martinique, I want to replace the automotive distributor with a marine unit for liability reasons (did not want new owner to sue me). So I purchased a NOS point type Prestolite distributor and dropped it into my 351W. Never has the old girl run so good. Poor idle quality disappeared (but, I also replaced a worn out carburetor at the same time). The engine started effortlessly and ran beutifully.

So, it is very possible that your current distributor is simply worn out. The bearings/bushing could be shot. I suppose when tightening down the clamp bolt, you are causing the shaft to shift in the bearing and it starts to wobble. this wobbling could cause erractic behavior of the triggering device in the electronic module. I suppose your distributor could be cracked. Might explain the issues when tightening the clamp.

So, look on Ebay and buy one of those NOS Prestolite point type distributors. Remove your electronic module and install it in the new distributor and go from there. I would bet it will solve your problem.

all of that is inside of the dist. and the only way tightening the bolt to the housing could effect that is if the base housing of the dist is cracked. I would say something in the clamp block is off, like it's the wrong style/application or the dist is not seated correctly.

I ordered a NOS rh distributor. It should be here on Friday. Can anyone direct me to a descent step-by-step on the change out of the distributor? The electronic conversion should just set right in the same as the old, I just need to run the wires.

What I think I know:

Pull the old distributor out, mark number one, put new in one tooth back. If this doesn't work, I need cylinder 1 at top dead center and the rotor at the number one plug. Get it to start and set the timing to 6 degrees before top dead center at 600 rpm.

Obviously it will be my first so be gentle!

Thanks in advance

When you get your new distributor, compare the shaft and gear of the new one to the old one. Measure how far the end of the gear is from the base of the housing on both units (as as possible). Also grasp the gear and try to move it latterly on the old distributor and see if you can sense any play in the bushings. Let us know what you find.

What dropped...the srew driver or the pin

Thats a new one for me...I wonder if you can fish it out with one of those skinny extention magnet things you see at auto stores...if there is room enough?????
Someone else...chime in.

Wasn't part of the distributor. If you look down the hole where the distributor shaft seats, there was about a 4mm pin that looked as though it would fit into the center of the distributor shaft. That is what dropped loose, not the screwdriver or part of the distributor.

I might be able to fish it out with one of those magnets but I doubt it. I may have to take he oil pan out to do it.

Anyone know what it could be that dropped? It wasn,t part of the new distributor, it was there after I pulled the old one.

I'm betting it's the shaft to the oil pump and you need to pull the pan.

OK

I pulled the oil pan, reset the oil pump shaft, seated the distributor properly with the pump shaft.

The nos rh prestolite I ordered was the screw-down cap type, my old was the clip kind. So I couldn't use the old electronic ignition. I am going to order the new ignition from skidim. I was going to just use the points this season but I can't seem to get any spark from the coil after moving the red wire to the opposite side of the resistor (opposite of what it should be with electronic ignition). I guess the reset or breaker could be bad. Instead of fixing that, I am going to get the new electronic ignition for this distributor.


Question: In all of my efforts to reset the oil shaft pin, I have lost the position of the original distributor. I put the big wrench on the crank and rotated it to 0 degrees, noted the position of the rotor, then assumed that would be number one cylinder. Is that correct or do I need to do something else for top dead center at number one cylinder?

All I need to do now is hook up the new electronic ignition on Wednesday (shipping time) and figure out how to get distributor and number one cylinder at a good starting point to them set the timing.

I hope this answers the question of why it was running so bad. I think it will.

Just waiting for the electronic ignition. Also on some info on top dead center for number one cylinder.

Don

nuttyskier2002, I have the distributor perfectly seated into the oil pump shaft already. From what you are saying, I need to pull the distributor up and out again? Then get the compression stroke by bumping the motor, then hand rotate the harmonic balancer position to 0 degrees. Try to seat the distibutor with the rotor position noted, this will be where the number one plug starts. Then run the rest of my plug wires per my firing order. Rotate the distributor about 10 degrees clockwise, Start the motor and set the timing to 6 btdc at 650 rpm.

Thanks again for all the help.