I/O (Sterndrive) Conversion to Outboards

[Lpgc]

How long do the new engines need to be run-in for before you can get it on the plane / try full power?

 

[Scott Danforth]

10 hours for breakin

 

[redneck joe]

does break in not include WOT for a small period of time? I seem to remember a log book my dad kelp in breaking the twin 60s in on the starcraft back in the late 70s.

 

[alldodge]

https://www.clyde-outboard-services...on/honda-outboard-motors-running-in-procedure

 

[Pmt133]

As I recall from merc:
No extended periods at idle/below 1500 rpm
First ten hours no more than 3/4 throttle and vary throttle constantly
Next ten no more than 5 minutes at wide open. And cary throttle.
Engine is broke in at 20 hours.

I would assume like most modern vehicles that current break in procedure is more for the gearcase now than the engine. Modern ring packs seat fairly quick. And if they don't... well they don't.

 

[tpenfield]

I’ll just do what the manual says, but I think the link that AD posted is about right.

i think also I can watch the fuel consumption, as that can be an indicator of being ‘broken in’.

 

[redneck joe]

i've always had an issue with the term 'broken' in. pretty ominous imo..

 

[tpenfield]

i've always had an issue with the term 'broken' in. pretty ominous imo..

Yes, broken-in, but not broken . . . apparently the term came from the 'breaking' of horses (so they could be ridden).

According to AI . . .
"The term "broken-in" (or "break-in") originated from equestrian terminology. Historically, it described the process of taming and conditioning a wild horse to accept a rider and tack. By the 19th century, the phrase was adapted to mechanical assemblies to describe the initial wearing-in of moving parts."

 

[Lpgc]

i think also I can watch the fuel consumption, as that can be an indicator of being ‘broken in’.

I might expect the engines to become a little more economical when run in but I would think it difficult to judge when they're run in on that basis.

Wouldn't it need to rely on you already knowing fuel economy for fully run-in engines, while you probably won't know that unless you've already had the same engines on the same boat (and were now replacing run-in engines with new engines)?

If new / not run-in engines use more fuel than run-in engines it would be because of extra friction in new engines, but how much extra friction could there be before causing internal excesive hot spots etc more likely to damage new engines than help them run-in..

 

[tpenfield]

I might expect the engines to become a little more economical when run in but I would think it difficult to judge when they're run in on that basis.

Wouldn't it need to rely on you already knowing fuel economy for fully run-in engines, while you probably won't know that unless you've already had the same engines on the same boat (and were now replacing run-in engines with new engines)?

If new / not run-in engines use more fuel than run-in engines it would be because of extra friction in new engines, but how much extra friction could there be before causing internal excesive hot spots etc more likely to damage new engines than help them run-in..

I know it generally works with cars, so it may follow suit with the boat engines. I'd be looking for a change (improvement) in fuel consumption and not a specific value.

I've done this with cars and have seen a noticeable jump in fuel mpg around a certain mileage . . . it has ranged from 15K to as high as 25K when I noticed the improvement.

Time will tell if fuel consumption is a good measure. I have seen some comments about the engines (BF350's) not getting the fuel 'economy' the owners were hoping for . . . but maybe it is too early in the break-in cycle.

 

[redneck joe]

all manufacturers lie about fuel consumption

 

[Pmt133]

I've seen it both ways, people say they got significant fuel savings with them perhaps from older 4 strokes which were not anywhere near as efficient as the current crop is... and less than stellar results. Like everything else, highly hull dependent imo.

 

[jlh3rd]

I broke in my new 2021 Merc 115 hp. Recently did a check comparing current with break-in mpg/gph.....after 250+ hours......same.

 

[tpenfield]

I was getting around 1.2 mpg with the Mercruisers, so there is not room to go but up

 

[redneck joe]

yeah when we had the big boat we had twin 454's so about the same unless hull speed which we did often

 

[Pmt133]

I get 1.2 gallons per mile on the 330... and people claim diesels are more efficient.

 

[Scott Danforth]

BSFC is pretty much fixed at about 0.4# of fuel per HP per hr for a 4-stroke spark ignited motor

Diesels are about 0.333#/HP/hr

 

[Pmt133]

Yeah give or take. Turbo gassers are typically a little worse yet.

When they replaced the 330 with the 340 (smaller boat all around) they managed to get the triple yama bangs to do 1.00 mpg at cruise. Mind you that was nearly 10 year newer tech and a boat that was 10000lbs lighter.

 

[aspeck]

I wonder if my 1996 Johnson is "broke in" yet. I am waiting for the fuel consumption to improve ...

 

[tpenfield]

Quick Update . . .

I stopped by the re-power shop today to check on the fit of the trim tabs. Looks like I can cut the existing tabs down by 2" (making them 16" x 12") and they should be able to go back into the existing holes.

The engines are mounted and the steering parts should arrive later in the week.

.
With the engines mounted, the ventilation plates are about 1" up from the running surface. So, that will be the starting point for any tweaks in engine height.

The tilt clearance looks OK for both the cowling/swim deck and the LU tilt out of the water.

The tongue weight is certainly reduced with the engines mounted, probably in the 400 lb. range.