Trolling: Two Strokes or Four Strokes

[spiru]

i know a friend of mine who has e tec 75hp.consumpion is very good but he says that his engine is not happy trolling at low revs just like yours.surprisingly i have a 2 year old 50 hp two stroke mariner and it trolls very good for even 9 hours straight and i only changed the spark plugs after 150 hours.i even go sometimes trolling with live bait only 1.5knots just on gear and it works perfectly.

[rob1974]

Difficult to hit the nail on its head on this issue!!  As I said in a previous post elsewhere, my friend has a 50HP TOhatsu DI which does not give any trouble even though it is used for very slow speed trolling for hours at a strech.  On the otherhand, skip just said that Optimax motors are not prone to this problem; a friend of mine has an optimax (if I remember sorrectly a 125hp) which is prone to fouling the plugs if left working on low revs for a prolonged period of time.

Difficult call, but I have never heard of a 4 stroke having similar problems.


Rob

[skip]

Very interesting rob. Whilst the technology is the same, each engine series is designed and built differently, parts used, sofftware map etc. So perhaps one has to drill down deeper even to specific engines rather than just saying all optimaxes etc. What there does seem to be is a pattern of sorts, yet four strokes seem fine.

I still can't say for sure whether I would go down the direct injection route again for fishing. Yes for leisure on a budget without a doubt, still not sure for fishing.

[Destination Sea]

Hi
check this site they have tested various engine. their reviews seem good
http://www.boatsales.com.au/ under new and reviews heading drop down list to engines.

[skip]

Interesting to read that the Optimax 90 isn't considered as good as the ETEC 90 for low rpm trolling:

http://www.boatsales.com.au/boat-review/2984735.aspx

I think that correlates with the fact that DI outboards are good leisure engines but perhaps not ideally suited to fishing for extended periods of time/heavy use??. At least in the sub 100hp range. We need more reports from people to build an accurate picture.

[anglers]

I have a Trophy fitted with a 150 optimax which I use a lt for trolling . I find its a great outboard but I only had the boat for about 4 months so I cant really say what will it do in the long run. All I can say that during the Lampuki season I go out for about 12 hours on the go at low revs . Trophy boats and mercury suggests you get the optimax version if you are going to use the boat for fishing. My brother has a 115 yamaha 4 stroke on a 19 ft boat and it also does a good job but my brother recons the old 2 stoke were much heavt dutier outboards. I think the only drawback on the optimax is that is a load engine compared with a 4 stroke

[skip]

Hi anglers, the 150 is very different to the 90 in terms of block size etc, the comment referring to the article was comparing the 90 so I wouldnt worry about yours in that sense.

Good to hear it runs well, what did you mean by load engine compared with a 4 stroke?

Btw did you buy your boat locally new?

[anglers]

Sorry that was a misprint. The only drawback in my opinion on the optimax is the noise, it is a loud engine compared to the 4 strokes. Yes I bought my trophy locally and I think its the only 2008 model on the island.

[skip]

Ah okay makes, sense...who's the agent? Stand Marine?

[anglers]

The agents are Bayliner ( Glassfiber Industries ) mriehel

[skip]

Guys the more information you can post about the performance of your engine the better to help build the best picture possible when looking at 2 stroke Direct Injection engines and 4 strokes, both of which are modern ECU controlled engines.

Information that would be useful to include:
Length and approx dry weight of boat
Engine size and year
Any accurate fuel burn information you have.

Your overall experience with the engine to date.

[skip]

After testing this summer with my Tohatsu 90TLDI (ECU controlled direct injection engine) I can report that whilst consumption at trolling rpm's is pretty low, the engine, at least my engine is not happy running at lower rpm's (<2000rpm) for extended periods of time - >10mins without giving an rpm drop / hesitation before resuming.

Every time it does this I try and give it a quick burst of rpms for a few seconds to avoid over fouling the plugs. It's not that the engine stops or dies but its definately not happy.

It could be the software parameters that Tohatsu use, ETECs and Optimax's which are also DI engines seem to be okay at low rpm's for extended periods of time. Or it could be I have some kind of issue with my particular engine, the only way to know would be to compare with another 90ETEC owner.

Time to update the above.......

The boat stayed in the garage for most of the winter as they invariably do and I didn't have any time to dedicate towards it. However a few weeks ago I got on the phone to Mecca Marine after receiving several reminders that the parts we thought I needed under warranty had arrived in October and had been waiting every since.

Mecca arranged to have their mechanic Robert come over and we spent a good 4 hours carefully checking over everything. Robert was very methodical in his approach and checked all the wiring carefully at the console but didn't find any issues. Initially the ignition had been suspected as being faulty so Mecca also supplied a replacement ignition just in case, but it soon turned out not to be the case after it was noted that a couple of pins in the main engine wiring loom looked suspect and perhaps weren't making a good contact.

Robert returned with a new harness and instantly confirmed this was the issue after using the onboard ECU diagnostics. We went about replacing the wiring loom which Mecca had in stock, it was quite an ordeal to pass it through the rigging tube but with some tricks of the trade we managed!!

Last Sunday there was a break in the weather and my busy schedule so I took the boat out for a test. It ran brilliantly and we did around 20 mins trolling in the rpm range that was previously giving me problems....except this time no problems whatsoever. I was running the Tohatsu TCW-3 non Bio which I prefer over the Bio and no hint of smoke at all even on acceleration so a very nice clean burn.

Alungi season is fast approaching which will mean extended trolling use for a few hours but I am now confident that I won't have any issues and my 90 TLDI has me smiling again. I like the fact that Mecca got the parts into stock really quickly in addition to some parts which i didn't end up needing but they got just in case to be sure and make sure there would be no extra downtime if they were needed.

[benri]

Great Skip. Glad you managed to solve it!