Evinrude water passage blockage.

[valvebounce]

I have a 1963 18hp Evinrude,I've replaced the coils plugs points and impeller,it runs quite well.I was not getting much water from the cooling outlet.
After seeing a post on here saying the water system might be partially blocked I decided to check it.I found a partial blockage in the outlet orifice in the thermostat housing.I ran the engine in the tub and added a fair squirt of washing up liquid,The water turned oily(black)The engine struggled to get water through at tickover before I did this,and steamed a little.It now puts out plenty of water on tickover.
Although the spark plugs had only done a few hours,the centre peg had burned down on both plugs.(45 thou gap)I put this down to the engine overheating because of the reduced waterflow.
The black oil bothers me a bit,is there any way the gear oil can get into the .water system?
I have checked the gearbox oil level and it is spot on and as clean as when I replaced it.

 

[oldboat1]

Plug gap should be .030. Use Champion J4Cs (replaces J4Js): http://www.fiberglassics.com/library...service001.pdf

Do a compression check.

Can pull off the lower unit and flush manually up the tube (motor off). Flush down and around through the t.stat opening as well. You may have already cleaned out the soot (good) but may have overheated the motor (not so good). If it's up and running, just letting it run can do wonders. Lower unit has to be sunk about half way up, and if in a barrel let the hose run to keep the water from overheating and get rid of the exhaust nasties.

Outboard head temps (surface temp) should be in the range of 120-140F. Anything over 160 is overheating.

 

[F_R]

Spark plug gap wear is normal. Material (atoms & molecules) is simply being eaten away by the spark. That is why you change spark plugs as part of a tune-up.

Your description sounds like you have the water flow problem fixed

Black glop in the water barrel bothers everybody. But fear not, it is normal. You will find it is much cleaner on a boat on the lake where it was designed to run.

 

[valvebounce]

Thanks for the info O1,when I replaced the impeller I flushed the system through,I think leaving it overnight in the tub with it submerged well over halfway,and the action of the washing up liquid must have released a build up of stubborn sooty oil deposits.I have never been quite satisfied with the tickover,just by ear and experience.Like you say,leaving it running seems to work wonders.I left it running after the blockage cleared for over an hour,the tickover never missed a beat,and there was a good strong water ejection.
Here in the UK(Manchester)it's becoming hard to access Champion plugs,now I have your plug specs I'll have a look on the net.
We seem to only have access to NGK plugs,they recommend B6S for the standard ignition and B8S for the supertwin.
I ran Motocross bikes on NGK racing plugs a few years ago,and they didn't last long,I swapped over to platinum plugs and the difference was amazing.
I'll do a compression test like you suggested,but I think the compression is ok.The throttle response is very good and snappy,which to me usually means the motor is in good condition.

 

[valvebounce]

Thanks FR,you have put my mind at ease.Here in the Uk there are no lakes apart from one that I know about that permits 2 strokes.I usually go to a river 35 miles away to test the engines,but there are speed restrictions,to stay legal,you cannot get the boat on the plane.I plan to use the motor for sea fishing,but the sea is a 70 mile trip.
I envy you guys in the states,you seem to have a lot more freedom than we do in the Uk.Although we are an island,we still have to pay to launch into the sea.

 

[Vic.S]

I have a 1963 18hp Evinrude................

I'm also in the Uk so know the difficulty obtaining Champion plugs, but any Evinrude agent should be able to supply. I normally order spares from Oakley Marine ( aka Outboards Direct) in Brighton. Other users of the YBW.com boating forums have had good service from Wills Marine in Kingsbridge Devon.

B8S are the nearest equivalent NGK plugs and should be perfectly satisfactory in an old engine with points ignition. They are a fairly cool plug so if you have trouble with fouling when trolling try B7S or even B6S which are, as you will know, hotter grades.

For what its worth I have a set of Champions and a set of NGK for my 6hp Evinrude. If there is any difference in performance then the NGK ones are marginally better!

Reducing the gap from 45 thou to 30 thou should extend your plug life. If necessary open them up a little but no more than 40 thou.

It's an old engine esp if it has been used on salt water all its life ... look after it ...... I bet none of the modern far eastern built stuff will last half as long, Won't get parts for them either!

 

[F_R]

2-strokes not allowed in UK. That's interesting, didn't know that. Unfortunately, that seems to be the way we might be heading here in U.S. also. But except for a few places like CA, we can still use 'em.

 

[Vic.S]

2-strokes not allowed in UK. That's interesting, didn't know that..

Not exactly right.

Emission control standards introduced a few years ago by the European " Recreational Craft Directive" effectively put a stop to the import and sale of new 2 strokes for recreational boating use throughout the EU.

Commercial use not affected. Existing engines including those in stock in retail outlets at the time were not affected.

Modern fuel injected engines such as Etecs and Optimax comply with the emission standards so are OK.

The standards apply to all marine engines, including 4 strokes. Inboards as well as outboards. Also emission limits applcable to diesels but it is on two stroke gasoline engines where the biggest impact is felt.

Still possible for UK yachtsmen to buy small 2stroke outboards in the Channel Islands, which are not part of the EU, and ( ilegally) import them into the UK. Bit of a waste of money though if they get caught!

 

[valvebounce]

Thanks for the info VIC,after getting the correct plug number off OB1,I had no problem getting them on the net.(J4C)
I have 1998 25hp Johnson,there is an Iridium plug equivilent,I intend using them in it.(the 25hp)

FR-the restrictions are on mainly land locked lakes,most rivers permit their use.Like Vic says,it's illegal to purchase new 2 strokes unless they are for commercial use.The only lake I could use is 150miles away in Northampton.