1954 Evinrude Fleetwin Aquasonic 7.5hp 7514 Dead cylinder-Need Help

[Mark Fletcher]

Hi all, new member here. I have the above engine and I forgot to winterize it 2 years ago. I just found out a few days ago. :redface:

Cleaned the carb, tried to start and water in the top cylinder and zero compression. Bottom had 50 psi. It started and ran, but only on one cylinder.

I sanded the head and replaced the gasket. No water that I could tell, but still no compression.

I removed the aluminum exhaust baffle plate and there was a couple small holes. I patched with JB Weld and re -installed it.

One of my first steps was to check spark and it does spark. The coils look good through the hole in the flywheel. The points are set to .020" and are not pitted.

Upon checking the spark some more, it looks like it may be weak but I don't know!

Upon checking the compression again, I don't get a reading on either cylinder. I checked the gauge with a lawn mower and no reading on it either. It just bounces and will not stay. I checked it on my dirtbike and it has 132psi and the release valve works on the gauge. So I'm not sure what's going on there.

The good 'ol boy thumb over the hole method implies that there is good compression.

I'm stumped! I've never worked on a boat engine before and I don't know what else to do. How do I test the coils?

I know many of you probably don't care about an old worn out Evinrude, but I really like the engine. It pushes my 11' flat bottom jon boat great! Please help!

 

[oldcatamount]

Re: 1954 Evinrude Fleetwin Aquasonic 7.5hp 7514 Dead cylinder-Need Help

We all care about "old worn out Evinrudes" here. It sounds like you have a faulty compression tester. You can use an air gap spark tester to check ignition coils. Compression and ignition are the two things to test first.

 

[Mark Fletcher]

Re: 1954 Evinrude Fleetwin Aquasonic 7.5hp 7514 Dead cylinder-Need Help

We all care about "old worn out Evinrudes" here. It sounds like you have a faulty compression tester. You can use an air gap spark tester to check ignition coils. Compression and ignition are the two things to test first.

That's good news!

I can't imagine my compression tester being faulty since it's a good brand name and new, but its possible.

I'll try the air gap tester and post up the results. Thanks for the quick reply!

 

[Mark Fletcher]

Re: 1954 Evinrude Fleetwin Aquasonic 7.5hp 7514 Dead cylinder-Need Help

The spark test proved good spark. It jumps a 1/4"?

Is it possible for the top cylinder only to not get fuel? I did squirt some in the plug hole and there was no difference, so I doubt it's a fuel problem.

I inspected for cracks and didn't see any in the piston or the cylinders. The rings spring back when pushed on so they don't seem to be stuck.

I know all an engine needs to run is compression, fuel and spark at the correct time. One of these are off and I'm having a time figuring it out.

Even with low compression, I think the dead cylinder should hit at least every once in a while with the good cylinder keeping the engine going, but it's not. Could I be dealing with a timing issue?

It ran great once upon a time.

 

[lindy46]

Re: 1954 Evinrude Fleetwin Aquasonic 7.5hp 7514 Dead cylinder-Need Help

One carb feeds both cylinders. Have you checked for gouges in the cylinder wall?

 

[Mark Fletcher]

Re: 1954 Evinrude Fleetwin Aquasonic 7.5hp 7514 Dead cylinder-Need Help

It doesn't have any gouges in the cylinders, but there is some pitting present on the bottom of both cylinders from where water has sat in there. I didn't think it was bad enough to cause my problems though. It won't fire at all.

 

[nwcove]

Re: 1954 Evinrude Fleetwin Aquasonic 7.5hp 7514 Dead cylinder-Need Help

im curious about the headgasket you replaced.......was it an "all metal" gasket that ive seen mentioned in another thread? i think it was labeled as brp.

 

[Mark Fletcher]

Re: 1954 Evinrude Fleetwin Aquasonic 7.5hp 7514 Dead cylinder-Need Help

im curious about the headgasket you replaced.......was it an "all metal" gasket that ive seen mentioned in another thread? i think it was labeled as brp.

I believe it was all metal. Is that a bad thing?

 

[nwcove]

Re: 1954 Evinrude Fleetwin Aquasonic 7.5hp 7514 Dead cylinder-Need Help

not necessarily a bad thing, i just find it odd ! seems like it would be hard to seal unless the block and head were perfectly flat. another poster replaced a head gasket with one of those metal ones and now mentions low compression. ( the other poster did re-ring his 7.5, against the advice of some very experienced folk.....so the cause in that case , if that motor actually still has low comp, is still an unknown)

 

[Mark Fletcher]

Re: 1954 Evinrude Fleetwin Aquasonic 7.5hp 7514 Dead cylinder-Need Help

I don't know if you have seen them before, but they are not solid steel gaskets if that's what you were thinking. They are like a perforated steel with some other material mixed in as well. They do have some give to them. I've used this type before on other engines with no problems.

The bottom cylinder has enough compression to run, so I don't suspect the head gasket too much. There is no more water entering the combustion chamber.

 

[Mark Fletcher]

Re: 1954 Evinrude Fleetwin Aquasonic 7.5hp 7514 Dead cylinder-Need Help

By the way, I really appreciate all of the help! It's really bothering me that my good old engine isn't working any longer.

 

[oldybutagoody]

Re: 1954 Evinrude Fleetwin Aquasonic 7.5hp 7514 Dead cylinder-Need Help

I had a blown head gasket on my Fastwin that was letting water into the upper cylinder. I replaced the head gasket but still had low compression. I chased my tail till I removed the head again and found out the head was warped in the area between the cylinders. It cups out, preventing a proper seal. remove your head again and lay a flat straightedge (I used the edge of a feeler gauge) over the milled areas of the head and hold it up to a light. If you see light leaking, that's your problem. It seems like a pretty common issue with these old OMCs. It's an easy fix though. You'll have to lap the head to bring it back to flat. Do a search on here for "lap warped head" and you should find lots of help and pictures. It isn't hard but it takes time. Since you had water in the cylinder I would bet your head is warped.

 

[Mark Fletcher]

Re: 1954 Evinrude Fleetwin Aquasonic 7.5hp 7514 Dead cylinder-Need Help

I had a blown head gasket on my Fastwin that was letting water into the upper cylinder. I replaced the head gasket but still had low compression. I chased my tail till I removed the head again and found out the head was warped in the area between the cylinders. It cups out, preventing a proper seal. remove your head again and lay a flat straightedge (I used the edge of a feeler gauge) over the milled areas of the head and hold it up to a light. If you see light leaking, that's your problem. It seems like a pretty common issue with these old OMCs. It's an easy fix though. You'll have to lap the head to bring it back to flat. Do a search on here for "lap warped head" and you should find lots of help and pictures. It isn't hard but it takes time. Since you had water in the cylinder I would bet your head is warped.

I sanded the head down on a large piece of glass. Then I checked it with a straight edge against the light. It wasn't warped. I'm pretty sure the head gasket isn't my problem.

Is it possible to get the plug wires mixed up and it start and run on one cylinder? I'm out of ideas.

 

[Mark Fletcher]

Re: 1954 Evinrude Fleetwin Aquasonic 7.5hp 7514 Dead cylinder-Need Help

I have an old Seahorse (5.5 horse I think) that I know nothing about. I kept it for a parts engine because it shares some similar parts it looks like. I wonder if I can rob Peter to pay Paul on this one?

If not, I'm out of idears. Are there any suggestions on whether I should sell the engine or part it out?

 

[nwcove]

Re: 1954 Evinrude Fleetwin Aquasonic 7.5hp 7514 Dead cylinder-Need Help

id would beg, borrow or rent another comp tester....just to compare results. ( odd that it shows nothing on the lawn mower....the mower does start ok and run well??) the motor could be ok, and just need some tlc on the ignition and carb. dont give up quite yet!!

 

[Mark Fletcher]

Re: 1954 Evinrude Fleetwin Aquasonic 7.5hp 7514 Dead cylinder-Need Help

Yes, you are right…I'll ask around, but off hand I can't think of anyone close by that will have one. All of my friends and family come to me to work on stuff. So, we're all in bad shape. lol!

 

[1946Zephyr]

Re: 1954 Evinrude Fleetwin Aquasonic 7.5hp 7514 Dead cylinder-Need Help

Well, if it says "Aquasonic" on it and it's a 7514, then it's a 1954 Fleetwin with a 1955 cover. That trade name didn't start till 1955.

If you have a cylinder not producing compression, then it's a safe bet that your head gasket is blown. You might stick a pencil in through the spark plug hole and turn the flywheel to make sure the piston is still attached to the crank. It's not uncommon for the old Fleetwins to nuke out rods.

 

[Mark Fletcher]

Re: 1954 Evinrude Fleetwin Aquasonic 7.5hp 7514 Dead cylinder-Need Help

Well, if it says "Aquasonic" on it and it's a 7514, then it's a 1954 Fleetwin with a 1955 cover. That trade name didn't start till 1955.

If you have a cylinder not producing compression, then it's a safe bet that your head gasket is blown. You might stick a pencil in through the spark plug hole and turn the flywheel to make sure the piston is still attached to the crank. It's not uncommon for the old Fleetwins to nuke out rods.

Thanks for the reply! I actually just threw "Aquasonic" in there on my own. I thought mine was the same as the later model. Mine is just a Fleetwin then. Sorry!

I just replaced the head gasket and the rods are still attached. I need to find another compression gauge to borrow. It may not be getting any compression or it might have good compression and I'm looking in the wrong area…Thanks for the help everyone!

 

[1946Zephyr]

Re: 1954 Evinrude Fleetwin Aquasonic 7.5hp 7514 Dead cylinder-Need Help

Oh, okay. No biggie. The '55 was no different than the '54, mechanically. Both are matching twins, so, you're actually accurate. These years and up to '58 are awesome little motors. If your rods and pistons are intact, then you'll be in good shape. Keep your mix at 16:1 and that motor will run for years.

 

[Haffiman]

Re: 1954 Evinrude Fleetwin Aquasonic 7.5hp 7514 Dead cylinder-Need Help

Get a can of fogging oil, shake it good and 'foam' up the carb intake as much as you can.
Try to start.
Even if it does not start, it should be almost equal amount of fogging oil in the cylinders (wet plugs), or you have a problem at the suction side = crank case compression/vacuum.