Loss of power under load

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breitz
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Loss of power under load

I’ll try this again.  My M35 1995 has lost power under load.  Had 3000 rpm at full throttle.  Now about 2300 rpm.  In neutral it revs to the normal 3000 rpm.  A diver cleaned my prop.  My fuel system was bled of any air.  I’ve seen in posts others experienced this problem. How has it been resolved by the past victims.  If it revs fully in neutral and not in gear does this suggest any thing specific.  Someone suggested an injector problem but wouldn’t this. Affect thRevving in neutral as well.   Any suggestions will be much appreciated.  Thanks, Bill

Bill and Carla Reitz C-36 MK-2 1995 W/K Kind of Blue #1427 Sausalito Ca

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Siler Starum
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Posts: 101

We faced this issue unfortunately also yesterday, in neutral all OK and when clutched in the revs are dropping drasticly and the engine is almost stopping.
Starting normal, no smoke etc.
First thought was something in the propeller, however this appeared not the case so we managed to arrange a tow back home. 
Filters are OK and no condens/water.
A challenge today to continue figuring out the problem - my thoughts now are heading towards failing of the electrical diesel pump.
Something different then enjoying sailing without worries during holidays... anyhow having this kind of issues are not improving thrust in the M35B.

Durk Nijdam
S/V "SILER"
Catalina 36MKII - 2001 / hullnr. 2013
Stavoren - Holland

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Siler Starum
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Posts: 101

update from my side power-loss:

I checked the FO-lift pump with external 12VDC supply and the pump was nicely "ticking" and working. 

When the contact swich is in "on" position the lift pump should work already - which was not always the case and therefore I digged into the cabling again. 

I figured out that the 12VDC feed to the FO-Lift pump is in series with the LO-pressure switch, the bad/broken contact on the LO-pressure switch stopped the FO-lift feedpump causing not having sufficient fuel-supply with the power loss as result when more fuel was required under load.

So in our situation the problem is caused by a bad/broken contact on the LO-pressure switch.

Temporary by-passed the LO-pressure sensor whilst sourcing here for a new sensor which fits - so that at least we can continue our vacation. If the case will be that the engine will be destroyed due to low oil pressure there is at least a good reason to put a good engine like Yanmar in with the European parts center nearby and service points on almost every corner of the street here in Europe. (apololgies but the onliest issues we have with our Catalina 36MKII were till now mainly related to the Universal engine)
Presume anyhow to get an "original" one from Universal will be extremely expensive (due to all the new trade-sanctions introduced by the present USA big boss as for sure the part is produced in China) and will have a long lead time.

Positive thing is that at least now I know which one of the many different electrical diagrams I have is most likely the correct one, and can use this to dig furhter in the other electrical engine issue which has been put on the forum also many times already: the proper operation of the instrument panel (no revs, , hour counter working when it likes, far too high voltage indication), alarm buzzer not working (sometimes it does). During the winter season I measured all wiring through already, where no issues in cabling was found.

 

Durk Nijdam
S/V "SILER"
Catalina 36MKII - 2001 / hullnr. 2013
Stavoren - Holland

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KevinLenard
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Posts: 201

Just a heads up, on our '91 we were heating up to 190 degrees on the gauge at 2,000 RPM (I like to keep it at 180, but against a head wind/current I let it go to 190) and we get a reliable 7 MPH out of her.  Any higher RPM and the swim platform and exhaust start going under with no real improvement in speed and overheating.  (I put in a new thermostat recently.)

Turns out we had a broken engine mount on the forward starboard side that might have been broken for ages and this had led to the stern starboard engine mount nut coming loose (or the loose stern mounting nut led to the forward mount breaking).  Once I had the bracket welded and replaced I did the transmission flange to drive flange levelling exercise and levelled the engine on the starboard side.  I am fearful that I did some damage running her for many hours while off level, but the cutlass bearing seems OK, as do all the other fittings.  (She's up on the hard now due to our recent grounding incident...)

Once I did this she runs up to temperature at only 1,950 RPM and we still get the steady 7 MPH.  I'm not certain that checking the level of the engine did this trick, but it might be worth a try for anyone seeing a need to run at 3,000 RPM and/or running hot.

Kevin Lenard
"Firefly"
'91 C-36 Mk. "1.5" Tall Rig, Fin Keel, Hull #1120, Universal M-35 original (not "A" or "B")
CBYC, Scarborough, Lake Ontario, Canada

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LeslieTroyer
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Posts: 533
A rough alignment can be done on the hard, but needs to be repeated in the water. Check that your stuffing box isn’t too tight (hot while running).

Les & Trish Troyer
Mahalo 
Everett, WA
1983 C-36 Hull #0094
C-36 MK 1 Technical Editor. 

Commodore

 

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Chachere
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Posts: 822

One thing I would suggest you check -- particularly as you are on the hard, where you can do it without causing a flood! -- is the condition of the shaft tube (a.k.a. "shaft log").  If (as I gather from your description) the engine RPM loss was due to severe mis-alignment, its possible that the prop shaft was rubbing on the shaft tube.

If I'm remembering correctly, there is only maybe 1/8" (3mm) or so of clearance between the shaft and the  tube, and a bad misalignment can grind part of the tube away (necessitating a rather nasty repair job, as documented by yours truly and other members here: www.catalina36.org/forum/technical-discussion/shaft-tube-removal  ). 

 

Matthew Chachère
s/v ¡Que Chévere!
(Formerly 1985 C36 MKI #466 tall rig fin keel M25)
2006 Catalina Morgan 440 #30.
Homeported in eastern Long Island, NY

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Cuba660
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Posts: 22

I have the same issue with low RPM while in gear, 2100. I get 3200 Rpm in neutral. Did you find the cause? Seems like a fuel flow issue but not sure. I saw someone mentioned a bad fuel pump. Thanks 

Cuba Gonzalez
S/V Joyita
Chesapeake Bay, Harrington Harbour South
1994 Catalina 36 MkII #1326
Universal M35A

dhickmanii
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Joined: 7/27/18
Posts: 26

I had the same problem earlier this year.  It was a length of rope wrapped around the prop shaft.  Probably from a crab trap.   Before doing anything too crazy, bite the bullet and dive in to inspect the prop shaft. 

David
Mobile, AL
S/V Beach Belle
1983 Catalina 36 Mk I #154

Std. Rig, Fin Keel, M25

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Cuba660
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Thanks. I dove it and it was fine. I think I found the problem. I ran the motor and cracked open the fuel line to each injector one at a time. The first injector had no change in RPM, the other 3 had a noticeable difference in how the motor ran. That makes me think the first injector is not functioning. 

Cuba Gonzalez
S/V Joyita
Chesapeake Bay, Harrington Harbour South
1994 Catalina 36 MkII #1326
Universal M35A

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alfricke
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Posts: 80

Not sure if you got my last. Today my Parker Racor vacuum gauge reads 5 at full RPM and 1 or 2 at idle. When I close  the fuel valve at the tank part way when at high RPM the gauge reads 7 (start of yellow zone) After a bit the RPM drops dramatically and the engine wants to die. Runs fine at low RPM. To me, you have some kind of blockage upstream. Injectors could be a problem as well. I.E could have two things going on at once

Al Fricke
S/V Jubilee San Francisco Bay
Catalina 36' MkII  #1867
Universal 35-B

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Cuba660
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Posts: 22

Thanks. I saw your response on the other post too. i feel its the injector based on a simple test I did this weekend (although not sure how accurate this test is). I cracked open each fuel line one at a time at the injector. 3 of the 4 had a noticeable difference in RPM/motor sound, motor bogged down a bit. The forth one (most fwd one) had no noticeable difference in motor. A blockage there could cause the higher fuel pressure I'm guessing. I'll keep everyone posted on the other post.

Cuba Gonzalez
S/V Joyita
Chesapeake Bay, Harrington Harbour South
1994 Catalina 36 MkII #1326
Universal M35A

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alfricke
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Posts: 80

I apologize for any confusion I have caused. We have two very similar threads going at once (Kind of Blue and Cuba). There are some great ideas on both threads. Dirk on Siler has experienced and solved the little low oil pressure switch that can malfunction and keep the electric fuel lift pump from doing its job. I had the same thing happen several years ago while in a remote place and did a temporary fix the same way. Common denominator to most of the comments is fuel restrictions upstream from the engine but there can be multiple causes. Arghhh 

 

Al Fricke
S/V Jubilee San Francisco Bay
Catalina 36' MkII  #1867
Universal 35-B

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