Outboard weights

[GeorgeC]

Hello<br /><br />I hope some of you out there can give me the benefit of your knowledge.<br /><br />I have a 1980 Glastron T156 (Tri-Hull) with a Johnson 70 seahorse (J70FLCSA) from 1981. I am thinking of changing the engine for something new but have noticed that engine weights have gone up.<br /><br />My Johnson weighs in at about 102 kgs. The Tohatsu 2 stroke 70 weighs in at about 124 kgs and the direct injection model weighs in at about 146 kgs.<br /><br />Can my transom take the weight of these heavier engines? <br /><br />I know that when new the boat was rated up to 100 hp. Does anyone know what a 100 hp engine from the 1980's weighs in at? <br />Or for that matter a Mercury 90 (6 cylinder) which someone from the Classic Glstron Owners Club has on the back of his T156<br /><br />

 

[rickdb1boat]

Re: Outboard weights

For example, <br /><br />Your current Johnson weighs in at 224 Lbs, but is only a 70 HP.<br /><br />A Johnson 100 HP from 1980 weighs 301 lbs.<br /><br />A Mercury 90 HP 6 cyl from 1980 weighs in at 290 lbs.<br /><br />A mercury 115 6 cyl from 1980 weighs in at 295 Lbs.<br /><br />The Tohatsu 70 weighs in at 273 Lbs<br /><br />The direct injected 70 Model weighs in at 321 Lbs.<br /><br />You should have no problem with any of those engines that weigh around 300 lbs, providing your transom is solid. The current Tohatsu 70 you are looking at only weighs about 50 more pounds than what you have now. Hope this helps...

 

[GeorgeC]

Re: Outboard weights

Hi Rick<br /><br />Thank you very much for you information, it really is a great help.<br /><br />George

 

[bossee]

Re: Outboard weights

Hi,<br />If You want a new light 2-stroke 75-90 hp You can have a closer look at Mercury 75 or 90 Classic. They only weight 137 kg (302 lbs).<br /> http://www.mercurymarine.com/mercury_75_classic <br /><br />But even lighter is Yamaha 70 and 90 hp 2-stroke, only 104 kg (229 lbs) and 119 kg (262 lbs).<br />http://www.yamaha-motor.com/products/subc atspecs.asp?lid=5&lc=otb&cid=20&scid=10&but=38&year=2004&cat=Two+Stroke+Series&scat=Midrange<br /><br />If You want a 4-stroke, in 70-90 hp range:<br /><br />Yamaha F75/F90: 168 kg (370 lbs)<br />Mercury 75/90: 175 kg (385 lbs)<br />Suzuki DF70/Johnson 70 4-stroke: 152 kg (335 lbs)<br />Honda BF75/BF90: 169 kg (373 lbs)<br /><br />They are all carburated except Suzuki DF70/Johnson 70 4-stroke, they are EFI.<br /><br />I once read a change of a Johnson 70 hp 2-stroke (1991) to a Suzuki DF70 on a boat and the performance was amazingly almost the same regarding speed - not bad for an old 70 hp Johnson (they tested before and after engine change). DF70 was obviously better on fuel consumption and sound level. The negative thing was that the boat was more tail heavy with the DF70.<br /><br />If You want more speed a Yamaha 90 2-stroke is probably a good choice since it is also very light.<br /><br />If You want to take advantage of EFI, 4-stroke and CARB 3-star rating a Suzuki DF70/Johnson 70 4-stroke seems a good choice compared to what You have now, if the boat can handle the extra weight.<br /><br />Tohatsu 70 (or 90) TLDI is probably a good choice also, but they maybe is not so quiet as above Suzuki DF70/Johnson 70 4-stroke if that is important to You.<br /><br />/Bo

 

[lund17]

Re: Outboard weights

Is the Merc 75 and 90 built on the same chassis and if so doesn't it make sense to go for the higher hp/weight percentage as long as the pocketbook allows?

 

[UpstNYer]

Re: Outboard weights

It did for me Neil. An '04 90HP Merc Classic is going on my Fisher Avenger in March. Was looking hard at the heavier 90HP 2-stroke Johnson but, with a 73lb 9.8hp kicker already on the transom, didn't want to get too heavy back there. Rode around the bay with my old 40hp, the kicker, me and 140lbs. of sandbags in the stern just to be sure the 90 Merc wouldn't be too much. The 40 would just barely plane this combination.<br /><br />I have another question: Weights of 4-stroke 50hp engines are right in line with the weights of 2-stroke 50hp engines...a bit under 200 lbs. How come, in the 90hp range, there's a 50 to 100lb. penalty for going 4-stroke??<br />Bob