STUMPED

[kerstets]

I have an 81 dolphin with a 175 evinrude. When I run it at the house the motor runs great, even in gear, but when I'm in the water it won't do anything. As soon as I gas it up it bogges down and stalls. Any ideas?

 

[Trent]

Re: STUMPED

Time to clean and put kits in the carbs. Check the compression and make sure its firing on all cylinders.. <br /><br />In the water your putting a load on the engine (and exhaust back pressure). Most times its just the carbs that need a little help.

 

[twwmm]

Re: STUMPED

at the house is the motor at the same angle as in the water when the weight drops the stern or not much difference?

 

[JB]

Re: STUMPED

Hi, guys.<br /><br />I'll post this again. It probably needs to be repeated regularly.<br /><br />How an engine seems to run without a real load on it can be very misleading. Even a twin can look and sound great on one cylinder or with partial fuel starvation.<br /><br />Example: My friendly local shade tree wrench, who is an old-time genius on outboards just rebuilt a Suzi 85 for a customer. He fired it up on the ears for the customer. . . sounded great, revved fine even in gear. The customer was ready to hook up and tow it home, but Mark said no. He insisted on a dyno run, which the customer didn't want to pay for. I intervened and persuaded the customer that he should have it anyway.<br /><br />Under load only one (of three) was making power. Mark tore down the new carbs and found debris in two of them. The engine then dyno-ed 93hp.<br /><br />'Nuff said?

 

[kerstets]

Re: STUMPED

I had the compression tested thursday, and all 6 were between 105 and 110. As for the way the boat sits in my yard as apposed to in the water, I'd say in the driveway the boat sits the opposite way with the front of the boat lower. As for the carbs I will try that too.

 

[Franki]

Re: STUMPED

Hi JB..<br /><br />Just thought I'd ask..<br /><br />Who does Dyno's for outboards?<br />do they do flywheel or take of prop and hook to the prop shaft? <br /><br />I have wondered about dyno testing, and figured only the manufactures were equiped to do it..<br /><br />incidently, how much did the dyno test cost your friends client?<br /><br />rgds<br /><br />frank

 

[JB]

Re: STUMPED

G'Day, Franki!<br /><br />Mark's dyno fits onto the propshaft with prop removed. It is a big waterpump. He has a variety of "hubs" to fit almost any propshaft.<br /><br />By adjusting a restricter in the water flow, it measures the pressure that the engine is able to produce at top rpm and converts that to torque. A torque/rpm chart then tells him the hp being produced.<br /><br />I don't know who made it. Knowing Mark, he may have built it himself.<br /><br />I am assuming that if a Mom&Pop operation has one, almost any well equipped shop will also. Maybe I am wrong.<br /><br />

 

[Franki]

Re: STUMPED

yeah? <br /><br />I went and asked a few weeks ago at an outboard mechanics place near home, they have a mountain of old outboards around 15 feet high and covering about 30 meters squared.. and they seemed very well equiped, but they didn't have one..<br /><br />IF I knew of a way to calibrate it, I'd make one myself. <br /><br />Thanks Mr JB, <br /><br />rgds<br /><br />Frank

 

[kerstets]

Re: STUMPED

This may sound like the dumbest question of all but where do I add my oil in my boat? Its an 81 20ft dolphin center console with an 81 evinrude 175 hp