Johnson 70hp - How fast does it push your boat?

[Mark42]

Re: Johnson 70hp - How fast does it push your boat?

I'm a die-hard OMC guy, but have to admit that the 3 cylinder, 90hp yammies intrigue me. I have heard that some of the early models had some oil injection issues, but once that problem was worked out in later models years, the motors supposedly became pretty "bullet-proof."

I have also heard that they are very good on fuel in general and especially in comparison to OMC v-4s. I would think that this would be an excellent choice for your boat and I bet you would gets speeds in the 40 mph range.

Stray to Yamaha if you must - we will forgive you in the Johnson/Evinrude forums!


???

The advantage of the Yamaha over Johnson is about a 70-80 lbs weight savings, simpler design and better fuel economy.

Both the motors have legendary reliability.

The OMC does have low end torque associated with a V4, and should rocket the boat with a fast hole shot. Probably beat the yamaha to plane by 3-4 seconds. But I can sacrifice a few seconds of hole shot time for the weight savings.

I'm not straying far, I still have the Evinrude on the MFG!

 

[Mark42]

Re: Johnson 70hp - How fast does it push your boat?

Just a quick update, I ended up ordering a complete2002 Johnson 90 hp outboard motor from a rebuilder. Got tired of looking at used motors, calling about motors for sale on ebay and craigs list, emails and phone calls not returned, and spending the time and gas to drive all over to look at them. Only to come home empty handed and frustrated.

The motor has a complete powerhead rebuild, with gear case inspection and new seals, pressure tested, etc. The shop is also supplying flush mount (concealed) control w/tilt/trim buttons, oil tank and harness. A 1 year warranty on power head makes me feel better too. The shop also runs the motor in a tank to perform the initial power head break in, then the buyer has to follow the standard break in procedure.

Waiting paid off, got the motor a $150 cheaper than the price quoted just 3 weeks ago. That savings basically paid for the shipping. And I get my choice of color, so I went with Johnson white. The rep said that particular motor appeared to be a fresh water motor because it had no pitting on the gear case or internal cooling passages. That's a plus too.

The rebuild was less than the price of late model used 90 hp motors on ebay that I don't know their actual condition!

Just hope everything goes smooth, motor should arrive at the local Fed Ex terminal middle of next week.

 

[ezmobee]

Re: Johnson 70hp - How fast does it push your boat?

That's awesome Mark. Can't wait to hear how it performs on your boat.

 

[Mark42]

Re: Johnson 70hp - How fast does it push your boat?

That's awesome Mark. Can't wait to hear how it performs on your boat.

I am like a kid waiting for Christmas now!

Will take some pictures of the repower, maybe someone will benefit from them. This will be the second boat that I'm repowering, and using the same rebuilder. Only problem this time is the hoist mounted in the ceiling of the garage can't be used because the hard top won't clear the door. Will have to do the "tilt trailer to get motor off" trick.

Which reminds me, I better get started on building a motor stand for the old Force so I can run it when its up for sale.

 

[ezmobee]

Re: Johnson 70hp - How fast does it push your boat?

Mark, if you don't have video of the Force running and pushing your boat now.....go out and take one. I think it will be worth a couple hundie to ya

 

[Bob_VT]

Re: Johnson 70hp - How fast does it push your boat?

Great choice Mark!! Huge thumbs up.

That 90 will have you and the family flying along

 

[Mark42]

Re: Johnson 70hp - How fast does it push your boat?

Mark, if you don't have video of the Force running and pushing your boat now.....go out and take one. I think it will be worth a couple hundie to ya

Thats a good idea. Maybe I can get it over to the local lake this weekend and have wife shoot some video of the boat passing bye.

I do have video taken from the boat of the motor and wake from the last trip, but not of the boat from shore.

 

[trendsetter240]

Re: Johnson 70hp - How fast does it push your boat?

Congrats on your new motor! I know I'd be tracking the shipping every day until it was at my door!

Now I know you already found a motor but I thought I'd add my input anyways. (I must have been boating to have missed this thread earlier)

I have a 1995 70hp Evinrude, 15p 4 blade stainless prop and a 1300+lbs 17ft SS170v. This is a very deep V 20 degrees of deadrise.

I can just touch 35mph with a light load and still get 30mph with the heaviest load (add 600lbs or so). The key is choosing the right prop. 70 HP will move a lot of weight when applied to the correct prop.

Since you got a 90, you should be laughing all the way from hole shot to WOT.

Cheers!

P.S. Boat max HP rating is 100 and speed numbers were taken with GPS.

 

[joey nathan]

Re: Johnson 70hp - How fast does it push your boat?

My $0.02 1975 fiberglass tri-hull, '75 70HP Evinrude, no idea what pitch prop but oem supposedly 15. Good compression at 120, 135, 135.

With two 6 gallon tanks, me @ 220 lbs, and little else, I get 32 MPH on TomTom GPS. But this set-up is happiest at ~3800 RPM and cruising along effortlessly at approximately 25 MPH.

 

[Mark42]

Re: Johnson 70hp - How fast does it push your boat?

Wow, thanks for those update numbers. Hopefully the extra torque of the V4 and 20 extra horses will keep the old Bayliner moving along fine. Especially with the extra wind drag from the hard top.

Talked to Mike at 1outboard.com today (where I ordered the motor from) and he said the motor cowl, casings and lower unit are all taped up and headed to the paint booth.

It will be a real pleasure to have power tilt/trim on a 300 lbs outboard. I am so tired of pulling that darn Force up.... Looking forward to trimming up and idling into shallow water and being able to run in 24-30" of water with no fear of striking bottom or sucking up sand into the water pump when the prop or skeg does drag bottom. Something I can't do with the Force.

Now I have to order a OMC manual.

 

[ezmobee]

Re: Johnson 70hp - How fast does it push your boat?

Yeah you'll sure love TnT. I didn't have it on my '73 and tried for years to find a reasonably priced used unit to upgrade it. Never happened. I love that I have it on the '81.

 

[Mark42]

Re: Johnson 70hp - How fast does it push your boat?

Yeah you'll sure love TnT. I didn't have it on my '73 and tried for years to find a reasonably priced used unit to upgrade it. Never happened. I love that I have it on the '81.

When I changed the thermostat on the Force, there was about half a teaspoon of sand and a few of the baby snail shells in the housing. Amazing that they actually fit through the water intake grill, through the pump, and lodged in the thermostat housing. Guess I was closer to bottom than I had though on one or more occasions....

 

[phillnjack2]

if you go for a 1994 onwards johnson or evinrude 70hp you will be fine, they are built for better pulling on heavier boats.
with a 13x19 sst youl be over 40mph and vent the prop for good holeshot.
with the right prop youl probably see 45mph if that is the bowrider binliner.. the older omc 70hp engines (upto 1993) did not have the torque of the later ones.
Now as for the force 85hp that dont come anywhere near the omc 70hp engines for power or speed, they are pig engines, nothing at all about them can be compared to omc .noisy unreliable, un-economical and too expensive to keep going..
when looking around for a later 70hp make sure the compression is over 140 psi, preferably 145-150.on all 3 cylinders.

the old 60 65 and 70hp was measured at flywheel, the later 56 cu in engines are prop rated , so about 15hp more at the prop !!!
but the 1993 onwards are oval port and give the torque your looking for .


mine is over 43mph and that was with just the 60hp carbs and on a very bad hull for speed. my boat is not as quick as a bayline and its v hull.
but this gives and idea of what the later engine can be like, all up weight of around 1,300 pounds. and using a 13.5 x 15 alloy prop.36mph ran out at 6300,rpm
with 70hp carbs you can do the same with a 19 pitch sst plus top out at over 43mph easy.

 

[GA_Boater]

Ancient and now closed.