yanmar + harness

[vanpupi]

Hi,

First of all, if this question is already answered or I created a duplicate thread, I apologise.

I just made an offer to a Catalina 34 (build 1992) (owner accepted it  )
It has a yanmar in it (30 hp I believe).

I read on the forum/wiki etc that for the Universal engine the harness should be replaced. Is this for the yanmar engines also?
Is it the same replacement kit?

Are there persons who have some tips/tricks about the harness and a yanmar engine?

thanks !!!
Pieter

[r_bond]

Hi Pieter,

I believe the wiring harness was a concern thru 1991 boats and did not include Yanmar.  (If I've just mis-spoke...somebody PLEASE let me know!!!)  Apparently, there aren't too many of us with Yanmar engines - based on the limited responses I've gotten to postings I've made in the past.  However, I can tell you I've been very pleased with mine.  I have a 3JH2E model which is rated at 38HP. 

I did have one problem - the heat exhanger tank (which is cast aluminum) ended up corroding around the rear where the cap that covers the heat exchanger core is bolted.  Caps (front & rear) are brass so I ended up with some very severe electrolysis around the rear seal.  The only way to see this area is to take off the engine cover in the rear cabin.

You can reach over the front, top of the engine and "feel" around the cap and the exhaust flange.  I happen to do so and discovered some wet ooze - which prompted me to pull the rear cover to get a good look at the area.  Evidently there had been a small, slow leak around the back cap for some time. Never enough to show any dampness down below, just a slow insidious leak.    I was fortunate - found the problem JUST before the heat exchanger sprung a leak and lost all my coolant...and probably seized an engine.

Other than that, the little Yanmar has been extremely reliable and a good performer.

[Stu Jackson]

The wiring harness issue is a CONCEPT and MAY NOT be specific to Universal engines.

Here's the CONCEPT:  With an ammeter in the engine cockpit panel, ALL of the "juice" HAD to run all the way back to the cockpit panel and then back to the batteries for charging.  They ran it in a (relatively) little teensy wire, which induced tremendous voltage drop, so when you really needed "juice" to charge your batteries or to heat up your glow plugs, it just wasn't there.  It was also complicated by the rotten connectors they used.

So, regardless of what engine you have, YOU have to check for two things:

-- Do you have an ammeter in your cockpit panel?

--  What are the connections at BOTH the engine end AND the cockpit panel end?

If you have a voltmeter in your cockpit panel, you should still also check the connections.

If you have a voltmeter in your cockpit panel AND good connections, I would also check to find out where the alternator output goes on your boat. It should go to your house bank, but most likely goes to the 1-2-B switch.  If it goes to the 1-2-B switch, come back here and report and we can direct you to some good ideas for making things better.

Look forward to hearing from you.  Oh, BTW, what Yanmar engine do you have?

[Ron Hill]

Pieter : I doubt that you have an ammeter, but check for it anyway. I also doubt if your Yanmar had/has the trailer connector plug problem as the Universal engines did.

In 1992 Catalina started to wire the engines the correct way.  You need to check where the output of your alternator is connected to.  If your alternator output is connected to a terminal that goes back to the battery selector switch you're OK.  I'm not familiar with a Yanmar so I can't tell you where that might be?

In most of the 1988 production Catalina changed the engine instrument panel from an Ammeter(all 1986 & 1987 C34s) to a Voltmeter.  However, they had purchased a "boxcar" full of those old wiring harnesses.  So to use them up they still continued to run the alternator output back to the key switch and then back to the starter solenoid and finally back to the battery selector switch.
 
The old glow plug wiring problem was similar but differant - in that they ran all the amps(when turning ON the glow plugs) from the starter solenoid all the way back to the key switch and then finally to the glow plugs.  The glow plug solenoid addition eliminated 90% of that wiring amp loss. 

The new engines also have a differant glow plug and specificy only 10 seconds engagement !!

A bunch of thoughts

[vanpupi]

Hi Guys,

Thanks for all the advice.
Normally I'll see the boat again this weekend. I wrote down the things I have to look at and I'll post them as fast as possible.

The first thing I'll do is open the "engine room" and start following the wires from the altenator.
The boat is (as far as I could see) in very good condition, so I suspect to find the wires to go to the 1-2-B switch. But only one way to be sure ... :-)

I'll keep you informed :-)