1988 40HP Evinrude won't go full power

[sqzdog]

This is on a boat that is about 1100lbs so I know it is underpowered, but this thing does about 10mph with the bow in the air. I am wondering if something is off in the linkage that won't allow it to go. It shifts forward and reverse fine. Vent is open on fuel tank. Any ideas?

 

[racerone]

Perhaps running on one cylinder.----Test compression ----Test for strong spark.

 

[oldboat1]

Consider rebalancing load -- might be a little stern heavy.

 

[Tim Frank]

Is this a new symptom? Has it ever planed out for you?

 

[sqzdog]

I'll do the cylinder/spark test this weekend. I checked compression last time I was with it and it was consistent and within proper range.

As far as load, there is no load. I use a 5 gallon external tank that only had about 2 gallons in it.

This boat was given to me by a neighbor but hadn't been run in about a year. Carbs rebuilt 2-3 years ago.

It's almost like I am waiting for something to kick in and take off but it just never gets up and goes.

 

[oldboat1]

Measure spark with an adjustable open air tester (looking for sharp 7/16"). Not sure what hull you have, but can be hidden weight under the floor (water and water logged foam).

Tester similar to this:

 

[boobie]

Do a cylinder drop test on it when it's acting up.

 

[interalian]

Where's the trim pin set?

 

[Tim Frank]

Is this a new symptom? Has it ever planed out for you?

Did not think these were trick questions.

How long have YOU had the motor ?
Has it ever planed the boat in that time?

Hull could be waterlogged amongst other things.

 

[sqzdog]

Did not think these were trick questions.

How long have YOU had the motor ?
Has it ever planed the boat in that time?

Hull could be waterlogged amongst other things.

I have had the motor and boat for about 2 months. I have taken it out twice and wasn't able to get it to plane out. Was just to slow. I have felt under the hull but does not feel to be waterlogged.

 

[racerone]

Just took a 40 hp apart and found cylinders dry , no oil.------Also found a 21" pitch prop on it.-----Do not know what kind of boat it was on but 21" was likely too much pitch.----So do your trouble shooting.----Sounds like it is running on 1 cylinder to me.

 

[sqzdog]

Just took a 40 hp apart and found cylinders dry , no oil.------Also found a 21" pitch prop on it.-----Do not know what kind of boat it was on but 21" was likely too much pitch.----So do your trouble shooting.----Sounds like it is running on 1 cylinder to me.

Will do. I am actually prepping an Evinrude 88 SPL for the boat, but I'd like to make sure the 40 is ok so I can sell it.

 

[oldboat1]

I have felt under the hull but does not feel to be waterlogged.

should always feel water under the hull

seriously, would be wise to check the rating for your hull -- 40 to an 88 is quite an increase in weight and torque. Additionally, make very sure the transom is solid.

 

[interalian]

Does the boat weigh 1100lbs or is it supposed to weigh 1100lbs? Two different things. One that's supposed to weigh 1100lb is likely rated for a good size motor, probably north of 120hp. What does the rating plate say is maximum HP?

 

[sqzdog]

Does the boat weigh 1100lbs or is it supposed to weigh 1100lbs? Two different things. One that's supposed to weigh 1100lb is likely rated for a good size motor, probably north of 120hp. What does the rating plate say is maximum HP?

According to mfg, the boat weighs 1050 dry and is rated for up to 110HP. There is no plate on the boat, I had to research the model online.

 

[oldboat1]

Sounds like you should be fine. I would check the transom for rot (inner core) -- It's a DIY repair, if needed. The water logging that was mentioned is under the floor -- unavoidably collects rain water. Can drill a few small holes in the transom at the base, and see if there is water drainage. Also checks the condition of the plywood core, if relevant for your hull.

 

[interalian]

You can check the current weight on a roadside scale. Pretty quick way to see if it might be overweight due to water soaked flotation foam.