1966 Evinrude ski twin, no go, has sparks, runs on spray. no crankcase pressure?

[tsnapcracklepop]

I hope I am posting to this evinrude forum for mechanical problems.

1966 twin cyl electric start. Runs with a spray of ether, will not run on its own. My friend revived this boat after it sat for a few years by swishing out the tank, filling the tank, then taking out on water, where it ran about 3 miles, slowed down in rpms, and he limped back to dock at very slow speed.

I found the tank with tar on the bottom, and fuel system containing h2o and bad fuel. Cleaned system and replaced hoses, cleaned carb and fuel pump. Attached a temporary tank.

The bulb gets hard, and some fuel flows thru the fuel pump (cleaned and tested for positive and negative pressure off engine) by sucking and blowing, I can hear the diaphram and it pumps fuel off the engine when I suck and blow on the air line., )

When the engine is cranked by the starter, the bowl never seems to fill, by checking the drain. I am
checking float and needle valve today for setting.

Enigine will run with starting fluid, but not off fuel system. I have not put a guage on the crankcase attachment on the port side, but did check for vacuum and alternate pressure , while cranking engine, at the hose to fuel pump and at the crankcase nipple. I did this with my finger and detected NO pressure in either direction.

The engine runs great on starter fluid, but I suspect it may have a bad crankcase seal, losing fuel pump operation, and losing ability to draw fuel mix thru intake valves. When run on starter fluid, the bowl does not fill.

1) It seems like i should be able to at least feel some alternating pressure changes from the case nipple with my finger??

Also, I am not sure what the mechanism is on a shaft that runs from the flywheel on a lever down to a shaft which operates 2 ajdjustable tappets above the cylindder heads on the starboard side of the plugs. The top seems to run in a cog on the flywheel, similar to a recoil starter engagement. I do not see this mechanism in the field service mannual linked to this site on the powerhead diagrams.. It could be figure 3.1, which seems to be missing.

2) Compression release?

Appreciate any ideas! I have been lurking on this topic for a couple of weeks now, but have not yet nailed this down.

I am also revivng, for myself, a 1953 goodyear, which has sat for at least 20 years when I figure out this evinrude.

 

[gm280]

tsnapcracklepop :welcome: to iboats. Great to have you aboard...

Okay let's see if you can help you out some. I great way to check a fuel pump is by disconnecting the fuel line to the carb and cranking the engine. If fuel spews out the fuel line, the pump is working. As for the connecting a pressure gauge up to the crankcase, 2 cycle engines work with a pressure/vacuum setup so that the reed valve function correctly. So I don't think you will read any pressure because of the constant changing back and forth between pressure/vacuum. So that brings us to the lack of fuel delivery issue. First let me state this, STOP using ether or starter fluid in a 2 cycle engine. WHY? Because ether washes the oil out of the bearings and the engine runs without any oil lubricant. And that wears the engine extremely hard. A much better way to start such an engine is to mix up a little squirt bottle of 50:1 fuel oil mixture and use that to squirt into the carb opening to start the engine. That way when it does run, it is receiving oil protection as well... So no more ether or starter fluid. :nono: I suspect you have a carb issue with possible either a stuck float or needle and seat or even plugged passages. So buy a carb kit and disassembly the carb and clean it with some good carb cleaner spray and follow that up with some compressed air to blow out all the holes and passages. I think you will get that engine running then... JMHO!

 

[tsnapcracklepop]

Thanks RA. I am using a fuel mix with oil, but thanks for the reminder as it is important! Any idesas on the mechanism over the head?

 

[racerone]

If it runs you have crankcase pressure !-----Look into a good cleaning of the carburetor.

 

[tsnapcracklepop]

Thanks VA.

I read somewhere that the fuel pump runs off of positive pressure only, which makes sense, since the negative case pressure is used to draw the charge from the carb across the crank, up the intake, to the combustion chamber. the springs in the pump should reposition the pump diaphram. It seems that I should detect pressure thru that hose to the fuel pump..

I am returning to the carb now.

I still wonder what the tappet (2) mechanism does. The current adjustments on those tappets seem loose, but since it did run, I am not adjusting them. They do not have lubrication since they are outside of the engine. Will get pix.

tom in North KC

 

[racerone]

You read wrong !----The pump operates with a positive pressure pulse and also a slight negative pulse !!---Tappets ???---Are you sure this is a 1966 engine ?----Pictures of these tappets.----Is there an arm that goes to these tappets from the recoil starter ??---If so that is a compression relief for manual starter operation ?--And you should review your understanding of what happens in the crankcase to put fresh fuel into the cylinder.

 

[tsnapcracklepop]

Great VA. some limited 2 cycle experience with lawnboys and scooters. I never had to do anything to my 196 mecr 110 ob. heading off to the guys garage. back this evening. Yess, t has that arm, but has electric start/

tom off to the engine in NKC

 

[F_R]

A 1966 Ski Twin (33hp) does not have compression relief. Either you do not have what you think you have, or somebody has put a 1957 35hp powerhead on it. In any case those "tappets" if adjusted properly only open the relief valves while the recoil starter rope is being pulled. At all other times the valves are closed and do absolutely nothing.

I agree with all the above, stating that if the motor runs on both cylinders, the fuel pump is getting its required pulses from the crankcase. Of course, that doesn't mean the pump itself is any good, but you seem to indicate it is.

Have you checked the ignition coils? They are the Great Deceiver. Many people have mis-diagnosed those engines as having fuel problems when in fact it is an ignition problem. Those old coils have nearly 100% failure rate, unless they have already been replaced. Especially if you really have a 1957.

 

[tsnapcracklepop]

No Title

Well, down by the transom clamps, I find

Model # 35524

Serial #10125

It has electric and recoil start, and those are compression relief valves.

I have pix, but the phone isn't uploading right now, may try emailing them.

The forum will not let me back up from posting a photo, so i posted an unrelated one for your enjoyment

tom

 

[tsnapcracklepop]

No Title

pix?

 

[tsnapcracklepop]

other pix too large to post.

 

[racerone]

1961 model and 40 hp

 

[tsnapcracklepop]

yes, just found it at maxrules.com