Back to the main site

Changing pitch while at speed

B

Boatingbob

Active Member
Messages
42
Reaction score
1
I have a 2011 2274 Bennington with a Evinrude E-Tec. My partner likes to tow her grand kids around on a float while turning tight turns sometimes in choppy water. While doing this she sometimes changes the pitch of the motor. I think she lowers the pitch it in response to some cavortation in the chop and waves. I don't know why she raises the pitch. This is done in deep water. Is this apt to damage the engine? My concern is that raising the pitch might increase the chance of the engine sucking in air rather than water for cooling and that that could be hazardous to the engine.


Knowledgeable opinions are very appreciated.


Bob
 
I think you are referring to trim. When making tight turns with a pontoon you typically have to trim down (lower the motor) to prevent blow out, cavitation.
 
I trust you mean trim, not pitch. You really can't raise the trim high enough to not suck water. You would cavitate (subject the spinning prop to unstable water) long before then.
 
When towing for water sports............Keep the trim down!
 
Raising the trim, or rather fine tuning the trim, makes a cable steering setup easier to steer.  It also can help with acceleration, which is important when pulling tubes if the motor is small.  When I pull tubes I'm constantly adjusting trim because I don't have power steering. 


Sounds to me like your partner knows what she's doing.  I don't see how she'd do damage to the motor.  The prop will be mostly out of the water before the water intakes suck in air. 
 
Last edited by a moderator:
She kept adjusting the trim. After another day or so, the up adjustment was intermittent. After awhile longer the trim didn't work and the ignition switch wouldn't start the boat. We were dead in the water with three kids. Three or four hours later we got a tow to the dock. This will cost hundreds.


She searched the internet and I talked to a mechanic. Seems likely that the heavy use of the trim blew a fuse on the trim and throttle. Radio, horn, accessories work, but other gauges don't flicker when ignition is turned. RPM stays pointed at 3500.


Her internet searching results in lots of complaints about the circuit that the trim is on blows too often.


I continue to think that the gains of MANY trim adjustments wasn't worth it.


Bob
 
Sounds to me like the fuse is undersized...


A fuse doesn't blow due to constant current below its rating (or it shouldn't), it blows due to overcurrent (a fault or short circuit somewhere that shouldn't be there and causes excessive high current).  If the fuse was sized just barely above the constant current flow for the trim circuit, I suppose the fuse could warm up, and eventually melt, but it should not be sized that tightly above the normal current flow in the circuit.


Again, assuming there are no other issues or problems with any of the equipment in the trim circuit, I would ask Bennington, or the motor manufacturer, about using a larger fuse.


Again, a fuse is only there for HIGH current flow (like what happens when a short occurs that shouldn't) to stop a fire from occurring.  If it blows under normal use, either the fuse was weak, or just undersized.


I'm not saying just simply put a larger fuse in it, because the fuse NEEDS to be small enough to be the weakest link in the circuit.  Just putting in a larger fuse might cause a fire elsewhere.  But it could be a larger fuse will STILL be the weakest link, and the manufacture may recommend you change it to a larger fuse.  Which would be great, as that's a simple fix.  Anyway, that would be the line of questioning I would take up with the dealer/manufacturer.  Based on you mentioning internet searches, they are probably already aware of it.  Make a quick phone call.  Probably an easy fix.  Don't sell the boat just yet!
 
Last edited by a moderator:
I have a 2015 2375 RCW and also have the E-Tec. I adjust the trim multiple times on a trip based on speed activity depth of water etc... I have never had a problem with the fuse. If it is an issue with the specific model/year of your boat maybe you could look into having the trim switch wired to a dedicated fuse (by a qualified mechanic of course).
 
By the way, your comment about it being intermittent has me worried something else is wrong somewhere.  A fuse either works or it doesn't.  When it blows, it melts a big gap in the fuse and it CAN NOT start working again.  So, the intermittent part would have me worried...  Contact Evinrude.


Let us know what happens.
 
Last edited by a moderator:
Maybe the intermittent operation comes from an overheated trim switch (too much fiddling?). Could an overheated switch cause enough resistance to eventually blow a fuse?
 
I trim our boat every time I speed up or slow down. Always start down and adjust based on throttle. When tubing I'm all over the button without any issues. The trim actually makes a huge difference on our boat which I assumed wouldn't in a pontoon boat. Sounds like a deeper issue sorry to say. 
 
I use my trim as well but I would not consider it excessive or constant. Owned a boat for many years and never had a problem such as you report. Like others have mentioned, I think you may have deeper issues. Good luck...
 
I think it was intermittent in that the up switch on the throttle went out before the down switch went out.


More importantly ... a marine mechanic looked at it. The fuse was blown. Replacing that resulted in the ignition working, but the switch still didn't work.


Would anyone continue to maintain that using the switch multiple times for many 10 second periods is not likely to have contributed to the blown fuse and the broken trim switch?


Bob
 
The system should be able to handle such usage but I highly doubt it is a coincidence. 
 
You must log in or register to reply here.
Back
Top