85 evinrude looper idle timing

[Kerpit]

No Title

I'll attach some pics of how the engine is sitting right now. In the photos that you can see the river that was taken from another boat, i know for a fact the trim is NOT fully down. In the photos i was actually messing with the 15hp kicker so i bet the 140 trim was about mid way. Mid way in the slow moving "trim" bandwidth not "tilt". In the pictures you just see water and the engine, that is trimmed fully down. It does appear it's on it's lowest setting. I definitely understand that the propshaft should be parallel to the water in theory and trimming a bit further than that to get the bow up a bit produces more speed. I am mainly focused on getting the idle reliefs out of the water with it fully trimmed down. I only reference the relationship of the cavitation plate to the bottom of the hull to see if something isn't quite adding up. So when i raise the engine i'm planning to put it a bit above the bottom of the hull. My question is when i check this measurement am i trimming the engine up a bit to be level with the hull? Because fully trimmed down it's not even near parallel. This boat has always been like this since my dad bought it in the mid 90's. It's an 85 lund tyee 5.5. If need be i can remove the 15hp kicker to see how much stern rise i get. In these photo's the boat is empty. I verified there was no water in the bilge, but a full tank of gas and 2 people total in the boat. Normally this boat is pretty filled with Lake Michigan fishing gear.

 

[Kerpit]

No Title

 

[interalian]

That's deep, really really deep.

If you trim the motor so the cav plate is parallel with the bottom of the hull, does it sit lower than the hull? If it does, I'd want to jack the motor up until the cav plate is same or a smidge higher than the bottom.

*Edit: saw the picture, and the cav plate is a fair bit below the hull. You could move the motor up a hole for sure, maybe two.

Mine's not a looper, but sits a lot higher:

 

[Fed]

Does the boat have an external extruded keel?
That could limit how much you can move the motor up.

 

[Kerpit]

No Title

Thanks for the reply Fed. Can you please explain more? I attached a pic i zoomed in to see the keel. I'm not positive it's like that all the way to the stern.

 

[Fed]

It looks like it has one so maybe only raise it up 1 hole.

The boat looks very heavy at the back could it be water logged or have extra batteries for the leccy motor or an extra fuel tank?
Just looks heavy & low in the water.
Any history, how long have you had it, has it always been like this?

 

[Kerpit]

Extra batteries for the elec troller are normally up in the bow. They were out for this picture. The 15hp kicker is plumbed to run off the built in fuel tank. So there are no extra fuel tanks at the stern. There was no water at the bilge area in the stern. My dad bought this boat in the mid 90's and when i was younger i just know it never liked the no wake areas and never idled good for as long as i can remember. But i will try to dig up some old photos to see if i can find any references. I know my dad has never touched the engine height before. I'll guarantee he has no idea if the idle reliefs were always under water. He owns a body shop and pays no attention to mechanical detail! I'm a mechanic and absolutely the opposite!!! He re painted the boat and engines and had the powerhead rebuilt about 5 years ago just due to age. There was no catastrophic failure. This boat has been kept up at the lake house so i haven't seen it in quite some time as i haven't been up there. He brought it down so i could re wire it and just go through some engine and trailer maintenance. I'm really after this crappy idle. I want this to run flawless for him if possible. I understand it won't be like my i/o but i'm not asking for that either. When i sent the picture of the engine in the water to my brother who has used the boat more than me. He swears it never sat that low before...?

 

[interalian]

Might be a good idea to check the weight of your boat in case you have waterlogged flotation foam. Sometimes boats sitting on trailers fill with water and it gets in the foam. From what I can find, your hull should weigh 1200 pounds. Add ~320 for the motor, 50 pounds each for batteries, and 115 for the 15hp kicker. Not sure what trailer you have, but maybe 600 pounds or so? Roadside scales will weigh you for free if you don't hold up truck traffic.

 

[Kerpit]

Digging up this thread again. So we tore the floor up and the foam is dry and in good shape. Rebuilding the complete interior at the same time. While my dad is tackling that part i'm back at the engine. I'm going to raise the engine up a bit and installing boyesen reeds. The question i have now is should i be able to reach full throttle in reverse? I seem to have about 1/4 - 3/8 throttle in reverse and it was a pain to get the boat off the trailer last year. There was not enough throttle to motor off the trailer. You had to have the trailer really deep as if you were roping it off. I know some are controls are designed to have limited throttle in reverse. Can anyone confirm that i should be able to have more throttle opening in reverse or is that normal for an 85?

thanks again!

Brian

 

[jimmbo]

Your boat launchings must make for great entertainment at the ramp! If the boat does not come off the trailer at 1/4 throttle, try backing in further, or find a ramp that's deeper. Outboards and I/Os will lose thrust in reverse because the exhaust is being discharged in front of the prop. The engine unloaded(prop sucking exhaust) can very quickly overrev even being at 1/4 - 3/8 throttle. Another reason to limit speed in reverse is to prevent the boat from being swamped from water coming over the transom(a lot of old boats didn't have splash/motor wells

 

[Kerpit]

well maybe it's more like 1/16 throttle then! I boat every weekend april through november for 15 years, I know how to load/launch a boat! I am very aware of the exhaust aerating the water and causing high prop slip in reverse. In this case i'm not reaching much rpm. I'm not referring to reverse thrust. I also understand reverse can be limited so water does not come over the transom. I am seeking for someone who could possibly confirm this is mechanically limited on this particular engine so i can isolate my problem to the trailer. The trailer to this lund has been heavily modified over the years and is my dads boat. It is very possible that something as stupid as larger tires are causing the trailer to need to go deeper than normal (fenders barely exposed out of the water). It just did not seem to have much throttle in reverse meaning RPM! In my i/o i have much more throttle in reverse...

 

[jimmbo]

Your post did sound like you were trying to rev it at 4 grand to get off the trailer

On an outboard, since almost all the timing advance occurs before the carbs start to open, it is easy to limit throttle by limiting the timing advance with a mechanical stop controlled by the shift linkage thus limiting speed. On an I/O the throttle lever moves the carb/throttle body, not the timing plate, ands the advance is either mechanical or electronic and in either case the engine is free to rev up

 

[Kerpit]

Haha no 4k rpm launches!!! Sorry for the lack of detail in my post. Ok i definitely follow you there with the timing advance and rpm raise before carbs even open on a 2 stroke vs a 4 stroke with a distributor and mech or elec adv. I guess i just need to review the oem manual and look at the linkage when i'm at the boat next. I get it that i'm comparing apples to oranges with my i/o. It just seemed to be barely over idle. I really do appreciate all the help i receive on this forum.

 

[interalian]

Reverse throttle is limited by the control box. If you have a lot of slop in your control cables, you'll get less throttle than you would with tight ones. I can throttle mine enough to fill the motor well and I'd say it's around 1/4 throttle.